feat(tasks): tid på en opgave, og et træk i kalenderen sætter den

Bedt om: "jeg vil have tid på opgaver, og jeg vil kunne justere dem i kalenderen."

Serveren kunne det hele i forvejen — `due_date` og `due_time` læses sammen og
bliver til et `due_datetime` i kontoens tidszone. Det var fladen, der ikke havde
nogen vej til at sige det.

**Et felt i opgaveruden.** Tomt, indtil nogen sætter det: en opgave uden
klokkeslæt er det almindelige, og et felt, der åbner på 00:00, påstår, at noget
skal ske ved midnat.

**Og en fejl, der lå og ventede.** Serveren læser en dato uden en tid som "ryd
tiden". Så et gem af datoen alene tog klokkeslættet med sig — man rettede dagen og
mistede timen — og det samme gjorde hvert eneste træk i kalenderen. Ingen af
delene sagde noget.

`reschedule` siger nu tiden højt, tre måder, fordi de to første ligner hinanden i
JavaScript og derfor skal skilles ad ét sted frem for at blive forvekslet fire:

    undefined   behold den, opgaven har   — månedens ruder, hvor der ingen tid er at læse
    ''          ryd den                   — heldagsbåndet
    'HH:MM'     sæt den                   — et sted på døgnet

**Hvor på søjlen man slipper, er klokkeslættet.** Målt mod søjlens egen kasse frem
for mod siden, så det bliver rigtigt uanset hvor gitteret sidder og hvor langt der
er rullet. Rundet til kvarter: minuttet under markøren er ikke en oplysning, nogen
har — pegefingeren er bredere end et minut — og 14:07 er et tal, der ser ud som om
det blev valgt.

Prøven går hele vejen: sæt tiden, genindlæs og se at serveren tog den, ret datoen
og se at timen bliver, find opgaven på sit klokkeslæt i ugegitteret, og træk den op
i båndet igen. To ting, den lærte undervejs, står skrevet ved den: et træk over
fire hundrede pixels skal gå i skridt, ellers har browseren for få mellemstationer
til at holde gesten i live — og klokken skal være tidlig, for klokken fjorten
ligger under skærmkanten, og at måle noget dernede ruller siden væk under målet.

Co-Authored-By: Claude Opus 5 <[email protected]>

NOTES-SPEC.md

@@ -0,0 +1,437 @@
+# Notes, as verdande builds them
+
+A description of one working notes system: the data model, the syntax, the search,
+the rendering contract, the import and export formats, and — more useful than any
+of it — the decisions that look arbitrary until you know what they cost.
+
+It is written to be lifted into another program. Nothing here depends on Go,
+SQLite or Svelte except where it says so; where an answer was forced by the tool,
+that is called out so you can pick a different one on purpose rather than by
+accident.
+
+---
+
+## Read this part first: what to ask before you build
+
+**This document is not a drop-in. It describes a notes system that lives inside a
+task app with projects, roles, a trash and a search box, and about a third of its
+design is inherited from that.** Lifting it into a program with different
+surroundings without deciding which parts to keep produces something that works
+for a week and then fights you.
+
+**If you are an assistant working from this file: ask these questions and get
+answers before writing code.** Do not guess a default. Each one changes what you
+build, not just how you build it.
+
+### About the surroundings
+
+1. **Does the host app already have a place to file things** — projects, folders,
+   notebooks, tags? verdande deliberately gave notes no hierarchy of their own and
+   filed them under the projects that already existed. If your app has nothing,
+   you need an answer for where a note lives, and "a folder tree" is the expensive
+   one.
+2. **Is there more than one person?** Sharing, roles and "who wrote this" run
+   through the whole model below. Single-user changes the schema and removes about
+   half the permission surface.
+3. **Is there already a trash, and does it expire?** Notes lean on one. Without
+   it, deleting is either permanent or you are building a trash.
+4. **Is there an existing full-text index?** The search here is FTS5-shaped. On
+   Postgres it is `tsvector`, on a client-side app it is probably a scan, and the
+   ranking section below changes accordingly.
+
+### About the notes themselves
+
+5. **Markdown, rich text, or blocks?** verdande stores Markdown and renders it.
+   That decision is defended below; it is also the one that most constrains
+   everything else.
+6. **Is the first line the title, or is there a title field?** Both work. Deriving
+   it means one less thing to keep in step and one less thing a person can leave
+   blank, and it forces the rule "the first line is a heading" on the editor.
+7. **What links to what?** `#project`, `[[note]]` and task references exist here
+   because the app has projects and tasks. Yours may have none of them, or others.
+8. **Do notes carry files?** Attachments bring content-type handling, a store, an
+   authorisation path and an XSS surface. Skipping them is a legitimate answer.
+
+### About scale and language
+
+9. **How many notes, realistically?** Several choices below flip at around ten
+   thousand: the list payload, the search fallback, rendering the whole list.
+10. **Which languages?** The folding described under *Search* is Danish. Every
+    language has its own version of that problem and the generic answer (strip
+    diacritics) is wrong for several of them.
+11. **Where does the text end up besides the screen?** Search indexes, AI
+    features, exports and backups each read it. Plaintext makes all of them cheap
+    and makes a stolen backup expensive — see *What is still open*.
+
+### About integration, specifically
+
+12. **Who owns the note's identity — you or the other system?** If notes will sync
+    with something else, ids and timestamps are the whole problem, and the
+    `updated_at` rule below becomes the first thing you have to change.
+13. **Is this a read of somebody else's notes, or the store of record?** A copy
+    needs conflict rules; a store of record needs export.
+14. **What happens to a note whose project, task or link target is deleted?**
+    Answered here as "the link goes dead and the note is untouched". If your host
+    app cascades instead, say so before the first delete.
+
+---
+
+## The shape of a note
+
+```
+id           an opaque string, unique
+project_id   nullable — where it is filed, or loose
+title        derived, never set by a caller
+body         Markdown, the whole note
+created_by   nullable — survives the account being deleted
+pinned       favourite; the list puts these first
+archived_at  nullable timestamp — put away, not thrown away
+deleted_at   nullable timestamp — the trash
+created_at
+updated_at
+```
+
+### Markdown in a column
+
+Not rich text, and not a format of our own.
+
+Export was a requirement before a line was written, and **if the stored form is
+the exported form there is no conversion left to lose anything in.** A note stays
+readable by any editor on the day the program is gone. It is also what makes
+search and anything an AI does over notes cheap: both read text.
+
+The cost is real and you should know it before choosing: everything the editor can
+do has to survive a round trip through Markdown, and anything Markdown cannot say,
+the editor must not offer. There is no place to hide a feature.
+
+### The title is the first line
+
+Always, and re-derived on every save — not "when it is empty".
+
+Derived once and then left alone, a title goes stale the moment somebody rewrites
+the opening of a note, and the list ends up calling a note by a name that is
+nowhere in it. **The column is a cache of the body, not a field beside it**, and no
+caller can set it, so every caller gets the same answer.
+
+This forces one editor rule: a new note opens on its title, and the first line is
+styled as a heading. Otherwise a note whose first line is a sentence is a note
+named by its first sentence.
+
+### Archive and trash are two different bits
+
+The trash says *this was a mistake, and in thirty days it is gone*. The archive
+says *this is finished, and I do not want to read past it.*
+
+A twelve-hundred-note import is exactly the case where most notes are worth
+keeping and almost none are worth looking at. Without an archive, the list is the
+whole archive forever, and finding this week's note means reading past a decade.
+
+Both are nullable timestamps rather than booleans: *when was this put away* answers
+questions a flag cannot, and it costs the same byte.
+
+---
+
+## Filing: no hierarchy of its own
+
+A note belongs to a project, or to nobody.
+
+The reasoning is worth repeating because it is easy to talk yourself out of:
+projects already exist, are already shared, already have roles, already have a
+trash. **A second hierarchy to file things in is one too many**, and a note filed
+under a project inherits every one of those answers instead of needing its own.
+
+- A note with a project: everybody who can read the project can read the note; an
+  editor can change it.
+- A note without one: the author's, and nobody else's.
+
+Sharing a note *is* filing it in a project. There is no access list of its own —
+a second way to give somebody access is a second place to get it wrong, and the
+two would disagree the day one of them changed.
+
+---
+
+## Links: three kinds, parsed out of the text
+
+The body is the truth. Links are an index over it, rebuilt on every save.
+
+| Syntax | Means | Notes |
+|---|---|---|
+| `#project` | a project | Same characters the task quick-add parser uses, on purpose |
+| `[[a note]]` | another note, by title | The spelling every note app has settled on |
+| `/opgave/<uuid>` or `task:<uuid>` | a task | What a link pasted out of the app carries |
+
+Patterns as used here:
+
+```
+project   (?:^|\s)#([\p{L}\p{N}_-]{1,64})
+note      \[\[([^\]\n]{1,200})\]\]
+task      (?:/opgave/|task:)([0-9a-fA-F-]{36})
+```
+
+Three decisions inside that table:
+
+- **`#Firma` in a note means the same project as `#Firma` in the task box.** Not a
+  second kind of tag that happens to look alike. That is the whole of "tag a note
+  and see it in the project".
+- **The link table is torn down and rebuilt on save, not diffed.** A body is small
+  and the set is small; a diff is a second description of the same fact, and it
+  can disagree with the text. That is the one thing this must never do.
+- **The target is not a foreign key.** A link to something deleted is a fact about
+  the note. It should read as a dead link rather than vanish, and it must not
+  block the delete.
+
+The index exists so the question can be asked **backwards**: *what has been written
+about this task?* Answering that by searching every note's prose would be too slow
+to leave a panel open on.
+
+---
+
+## Search
+
+Three layers, in the order they answer.
+
+### 1. Full-text, ranked
+
+FTS5 over `title`, `body` and a folded copy, with `unicode61 remove_diacritics 2`.
+
+Ranking is bm25 with **the title weighted ten times the body**. A word in the title
+is what the note is *about*; the same word once in a long body is a mention.
+
+This matters more than it sounds. Ordering by "last touched" is invisible with ten
+notes and useless with twelve hundred imported the same evening: searching "Tesla"
+answered with a note about nginx first and the note actually called "Tesla Model Y"
+second — which reads as a search that does not work, because from where the person
+is sitting it is one.
+
+### 2. Folding, for the language you are in
+
+`remove_diacritics` does not touch `ø`, `æ` or `å` — Unicode considers them
+letters in their own right, not accented forms. So a Dane cannot find "grøn" by
+typing "gron", which is how people type when the keyboard is not theirs.
+
+The answer here is a generated column carrying a transliterated copy:
+
+```
+ø,Ø → o     æ,Æ → ae     å,Å → aa
+```
+
+indexed alongside the body and **weighted the same as the body** — otherwise a
+folded match outranks an exact one.
+
+> **Ask, do not copy.** This mapping is Danish. German wants `ü → ue`, Swedish
+> disagrees with Danish about `ä`, and Turkish has a dotless `ı` that breaks
+> naive lowercasing entirely. Get the mapping from somebody who types the
+> language.
+
+### 3. A word inside a word
+
+An index is built of tokens, and a token is whatever the tokenizer decided was a
+word. `gamerule keepInventory true` is three of them, and the middle one is
+`keepinventory` — so a search for "keep inventory" asks for two words that are
+nowhere and gets nothing, while the note sits right there.
+
+A prefix query gets half of it: `keep*` matches, `inventory*` cannot, and the two
+are ANDed, so the half that works is thrown away by the half that cannot.
+
+**This is not exotic in a notes app.** A decade of notes is full of commands,
+identifiers and file names, and every one of them is several words the index
+thinks is one.
+
+So: the index answers first; when it has nothing, the text is read, and every term
+must appear somewhere in the note, in any word. A `LIKE '%term%'` over the folded
+column covers title, body and language folding at once.
+
+What it costs: a leading `%` cannot use an index, so it scans. At twelve hundred
+notes that is a few megabytes and a millisecond or two, and it only runs when the
+fast path already came back empty — which is exactly the search that was about to
+disappoint somebody. **At a hundred thousand notes it is the wrong shape**, and the
+answer then is a trigram index, not a bigger scan.
+
+It does not rank. There is no match to rank — that is the whole situation.
+
+---
+
+## The list, and why the body is empty in it
+
+A list showing a title and ninety characters of preview must not fetch whole
+notes. Twelve hundred notes came to 3.9 MB, of which 98 % was body nobody could
+see.
+
+The important half is *how* it is trimmed: **the body is emptied, not shortened.**
+
+A field called `body` holding a *piece* of the body is a trap. The editor opens
+it, the autosave pause writes it back, and the note is now cut down to its own
+excerpt — destroyed by nothing more than having been looked at. Send `preview` as
+its own field and leave `body` empty; the client sees the empty body and fetches
+the whole note.
+
+That costs one more separation, and it is not optional:
+
+> **Which row is selected and which note is loaded are two different things.**
+
+The editor loads its text when the note's id changes. Hand it the excerpt first
+and the whole note second and the id is the same both times — so the second one
+never renders, and somebody sits looking at a note that had a title a moment ago.
+
+Highlight the row immediately from the list; give the editor the note only when it
+is whole.
+
+Rendering cost, separately: with twelve hundred rows, first paint took 2.1 s. CSS
+`content-visibility: auto` with an intrinsic-size guess took it to 0.95 s with no
+virtual list, no scroll maths, and no list that can fall out of step with itself.
+Try that before building windowing.
+
+---
+
+## The editor contract
+
+Rich text on top, Markdown underneath, and a source view that shows the file.
+
+The supported subset — deliberately small, because everything in it has to survive
+the round trip:
+
+| Block | Markdown |
+|---|---|
+| Title | `# ` |
+| Heading | `## ` |
+| Subheading | `### ` |
+| Quote | `> ` |
+| Code block | ```` ``` ```` with an optional language |
+| Bullet and numbered lists | `- `, `1. `, nested |
+
+Inline: `**bold**`, `*italic*`, `~~strikethrough~~`, `` `code` ``, `<u>underline</u>`,
+and images as `![alt](url)`.
+
+Five rules that were each learned the hard way:
+
+1. **Every line becomes exactly one block.** Markdown normally joins consecutive
+   lines into a paragraph. Here it must not: the person typed a line and expects
+   to get it back, and an editor that silently reflows what somebody wrote is an
+   editor they stop trusting.
+2. **Load on id change, never while typing.** Writing to the editor's HTML puts
+   the caret back at the start, which mid-sentence is unusable.
+3. **One definition of what a code block contains.** A copy button inside the
+   `<pre>` and a syntax highlighter reading `textContent` will disagree, and the
+   difference ends up in the file — a click on "Copy" wrote the word *Copied* into
+   the code and the next save put it on disk. Have one function that says what a
+   block holds, used by the highlighter and the Markdown serialiser both.
+4. **A note that cannot be rendered must not take the pane with it.** One note
+   arriving in an unexpected shape threw inside the editor's reactive effect, and
+   from then on *no* note would open — the previous one just stayed on screen. Put
+   a guard around the render, fall back to showing the raw text, and let the rest
+   of the pane keep working.
+5. **Escaping between tags and escaping inside an attribute are different jobs.**
+   An escaper written for text between two tags handles `&`, `<`, `>` — and not
+   quotes, because between tags they are harmless. Inside an attribute they close
+   it. `![" onerror="alert(1)](…)` is the whole exploit.
+
+---
+
+## Attachments
+
+Images pasted or dragged into a note, stored content-addressed by hash, referenced
+from the body as ordinary Markdown images.
+
+The security shape, which is the part worth copying:
+
+- **Served as `application/octet-stream` with `nosniff` by default.** Attachments
+  are the one place a user supplies content another user opens. An uploaded SVG or
+  HTML file rendered inline runs its own script on your origin with the session
+  cookie attached.
+- **One exception, as a named allowlist:** a short list of raster image types
+  served inline as their exact type — `png`, `jpeg`, `gif`, `webp`, `avif`, `heic`.
+  A note carries its pictures in the text, and served as octet-stream every one of
+  them is a broken image.
+- **The list is named one type at a time, never matched on an `image/` prefix.**
+  The prefix lets `image/svg+xml` through, and an SVG is a document that can run
+  script.
+- **The stored path is checked against the files directory again at read time.** A
+  traversal that somehow got into the database must not become one that reads
+  `/etc/passwd`.
+- **Reaching an attachment follows the note, which follows its project.** Same
+  chain as everything else. Do not let a client hand you the parent id and take it
+  on trust.
+
+---
+
+## Import and export
+
+The same format both ways: **a zip of Markdown files**, one per note, with a YAML
+front matter block.
+
+```markdown
+---
+created: 2019-04-02T10:15:00Z
+modified: 2024-11-30T21:04:00Z
+---
+
+# Møde med Anders
+
+Han vil gerne have kaffe hver uge.
+```
+
+- `created` / `created_at` / `date` and `modified` / `updated` / `updated_at` are
+  all accepted on the way in. Obsidian and Bear write this block; so should you.
+- Images travel in the zip beside the notes, and the links in the text are
+  relative — **a note and its pictures must end up in the same archive**, which
+  matters the moment an export is split into parts.
+- File names collide: two notes called "Møde" are two notes, and a zip with one
+  entry twice is a zip that loses one.
+
+Limits that a real import taught, all of them cheap to add and expensive to omit:
+
+- A ceiling on the upload, on the number of entries, and on the **unpacked** size.
+  64 MB of zip expanded to 66 GB is a normal shape for an attack.
+- A per-file limit as well as a whole-archive budget: one enormous photograph and
+  ten thousand small ones are different attacks with the same ending.
+- The entry name is never used as a path. Store by hash; the name is only a key
+  for rewriting links.
+- **Count what you skip, and say so.** A note whose name contained an ellipsis was
+  dropped silently by a filter looking for `..` — one out of 1141, found only by
+  counting at both ends.
+
+### Timestamps on the way in
+
+An importer needs to write `created_at` and `updated_at` from the file, and the
+normal save path must refuse to let it.
+
+`updated_at` means *when did this program last write this note*. Let any caller set
+it and the column means whatever the last writer felt like. Give the importer its
+own narrow entry point instead, and say in the comment why it exists.
+
+Without those dates, a move of twelve hundred notes is a pile that was all written
+the same evening — and the order they were written in is half of what an archive
+is.
+
+---
+
+## What is still open here
+
+Written down because a specification that only lists what works is a specification
+that lies by omission.
+
+- **Note bodies are plaintext at rest.** They hold API keys and passwords, and
+  they are in every backup anybody can download. Encrypting them is bigger than it
+  sounds: the body is in the full-text index and the folded column is generated
+  from it, so both are a second plaintext copy in the same database. Encrypt and
+  both have to go, and search has to be rewritten to decrypt in application code —
+  fine at a thousand notes, a full scan per keystroke at ten thousand, at which
+  point the answer is a keyed index (an HMAC per word).
+- **Import never merges.** Every run creates new notes. Say so out loud in the UI.
+- **There is no sync.** Export and the API are the way out.
+
+---
+
+## A short list of the traps, for the person in a hurry
+
+1. A `body` field holding an excerpt will be saved over the real one.
+2. Selected row and loaded note are two different pieces of state.
+3. The title must be re-derived on every save or it goes stale.
+4. Diacritic stripping is not folding, and folding is language-specific.
+5. A tokenizer cannot see a word inside a word; decide what you do about it.
+6. An attachment served inline is a script on your origin unless you allowlist by
+   exact type and send `nosniff`.
+7. Escaping for text and escaping for attributes are different functions.
+8. One render failure must not be allowed to freeze the whole pane.
+9. An unpacked-size limit is not optional on an archive import.
+10. Let the importer set timestamps; let nobody else.

web/e2e/smoke.spec.js

@@ -983,11 +983,11 @@ test('en opgave kan trækkes hen over et månedsskifte i uge-visningen', async (
 	// slipper der, hvor man kan se, man slipper.
 	await chip.dragTo(page.locator(`[data-date="${to}"]`), { targetPosition: { x: 30, y: 20 } });
 
-	// Sluppet på timesøjlen, landet i heldagsbåndet — og det er det rigtige sted.
-	// Et træk hen på en dag flytter datoen og sætter ikke et klokkeslæt, så opgaven
-	// har ingen tid at stå ved. `data-allday` er den anden halvdel af dagen: siden
-	// ugen blev et døgn, er en dag to kasser, og en prøve skal sige hvilken.
-	await expect(page.locator(`[data-allday="${to}"]`).getByText('skifte dæk')).toBeVisible();
+	// Landet i timesøjlen med et klokkeslæt: hvor på døgnet man slap, *er* tiden.
+	// Sluppet tyve pixels nede i en søjle, der begynder klokken otte, bliver det
+	// tidligt på dagen — hvad det præcist runder til, er ikke det, der prøves her.
+	await expect(page.locator(`[data-date="${to}"] .tevent`).getByText('skifte dæk')).toBeVisible();
+	await expect(page.locator(`[data-date="${from}"]`).getByText('skifte dæk')).toBeHidden();
 	await expect(page.locator(`[data-allday="${from}"]`).getByText('skifte dæk')).toBeHidden();
 
 	expect(trouble).toEqual([]);
@@ -1178,9 +1178,8 @@ test('kalenderen viser Googles begivenheder over egne opgaver, og kun opgaven ka
 	// få prøven til at bestå: det er også sådan et menneske gør det, fordi man
 	// slipper der, hvor man kan se, man slipper.
 	await task.dragTo(page.locator(`[data-date="${next}"]`), { targetPosition: { x: 30, y: 20 } });
-	// Landet i næste dags bånd: et træk hen på en dag flytter datoen og sætter ikke
-	// et klokkeslæt, så opgaven har ingen tid at stå ved.
-	await expect(page.locator(`[data-allday="${next}"]`).getByText('vande blomster')).toBeVisible();
+	// Landet i næste dags timesøjle, med det klokkeslæt der blev sluppet på.
+	await expect(page.locator(`[data-date="${next}"] .tevent`).getByText('vande blomster')).toBeVisible();
 	await expect(band.getByText('vande blomster')).toBeHidden();
 	// The events stayed where they were; a rescheduled task moves nothing else.
 	await expect(cell.locator('.tevent')).toHaveCount(1);
@@ -3210,3 +3209,97 @@ test('ugen viser et døgn, og dagene er lige brede', async ({ page }) => {
 
 	expect(trouble).toEqual([]);
 });
+
+/**
+ * Tid på en opgave, sat i ruden og justeret i kalenderen.
+ *
+ * Tre påstande, og den midterste er den, der var gået galt uden at nogen sagde
+ * det: serveren læser `due_date` og `due_time` sammen, så en dato sendt uden en
+ * tid *rydder* tiden. Et gem af datoen alene tog altså klokkeslættet med sig, og
+ * det samme gjorde et træk i kalenderen.
+ */
+test('en opgave kan få et klokkeslæt, og beholder det når den flyttes', async ({ page }) => {
+	const trouble = watchForTrouble(page);
+	await page.goto('/');
+
+	const box = page.getByLabel('Ny opgave');
+	// I dag, så den står på den visning, den skrives i — og i den uge, gitteret
+	// åbner på længere nede.
+	await box.fill('ringe til tandlægen i dag');
+	await box.press('Enter');
+	await expect(page.getByText('ringe til tandlægen')).toBeVisible();
+
+	// Klokkeslættet sættes i ruden. Feltet er tomt til at begynde med: en opgave
+	// uden tid er det almindelige, og 00:00 ville påstå noget om midnat.
+	await page.getByText('ringe til tandlægen').click();
+	const time = page.getByLabel('Klokkeslæt');
+	await expect(time).toHaveValue('');
+	// Tidligt på dagen med vilje: gitteret begynder klokken otte, så opgaven står
+	// lige under båndet og de to kasser er i billedet på én gang. Klokken fjorten
+	// ligger under skærmkanten, og et træk, der først skal rulle, er et træk,
+	// browseren taber.
+	await time.fill('08:30');
+	await time.blur();
+	await page.waitForTimeout(400);
+
+	// Gemt hos serveren, ikke kun i feltet: genindlæst og åbnet igen.
+	await page.reload();
+	await page.getByText('ringe til tandlægen').click();
+	await expect(page.getByLabel('Klokkeslæt'), 'klokkeslættet blev ikke gemt').toHaveValue('08:30');
+
+	// Og datoen kan rettes bagefter uden at tage timen med sig.
+	const date = page.locator('#due');
+	const day = await date.inputValue();
+	await date.fill(day);
+	await date.blur();
+	await page.waitForTimeout(400);
+	await page.reload();
+	await page.getByText('ringe til tandlægen').click();
+	await expect(
+		page.getByLabel('Klokkeslæt'),
+		'et gem af datoen ryddede klokkeslættet'
+	).toHaveValue('08:30');
+
+	await page.keyboard.press('Escape');
+
+	// I ugegitteret står den på sit klokkeslæt frem for i heldagsbåndet.
+	await page.goto('/upcoming');
+	await page.getByRole('button', { name: 'Uge', exact: true }).click();
+	const placed = page.locator('.tevent.task').filter({ hasText: 'ringe til tandlægen' });
+	await expect(placed, 'opgaven står ikke på døgnet').toBeVisible();
+	await expect(placed).toContainText('08:30');
+
+	// Trukket op i båndet over sin egen dag: så har den en dag og ingen tid. Den
+	// tomme streng siger "ryd", hvor ingenting siger "behold" — og de to må ikke
+	// forveksles.
+	//
+	// Et bånd, der er tomt. Prøven handler om at krydse mellem de to kasser, og en
+	// dag, hvis bånd allerede er fyldt af andre prøvers opgaver, gør slippunktet
+	// til en anden opgave frem for til båndet — hvilket er en anden gest end den,
+	// der prøves her.
+	const band = page
+		.locator('.weekgrid > .allday')
+		.filter({ hasNot: page.locator('.chip, .event') })
+		.first();
+	const today = await band.getAttribute('data-allday');
+	// Trukket i skridt frem for i ét spring. `dragTo` flytter musen i to træk, og
+	// over fire hundrede pixels i et travlt gitter giver det browseren for få
+	// mellemstationer til at holde gesten i live. Et menneske bevæger hånden hele
+	// vejen, og det er også det, der skal prøves.
+	const fromBox = await placed.boundingBox();
+	const toBox = await band.boundingBox();
+	await page.mouse.move(fromBox.x + fromBox.width / 2, fromBox.y + 5);
+	await page.mouse.down();
+	await page.mouse.move(toBox.x + toBox.width / 2, toBox.y + toBox.height / 2, { steps: 25 });
+	await page.mouse.up();
+	await expect(
+		page.locator(`[data-allday="${today}"] .chip`).filter({ hasText: 'ringe til tandlægen' }),
+		'opgaven kom ikke op i båndet'
+	).toBeVisible();
+	await expect(
+		page.locator(`[data-date="${today}"] .tevent`).filter({ hasText: 'ringe til tandlægen' }),
+		'opgaven står stadig på et klokkeslæt'
+	).toBeHidden();
+
+	expect(trouble).toEqual([]);
+});

web/src/lib/components/CalendarView.svelte

@@ -272,6 +272,15 @@
 		over = iso(date);
 	}
 
+	/**
+	 * Sluppet på en dag, uden at sige noget om klokkeslættet — så beholder opgaven
+	 * det, den har. Måneden er den her: en rude er en dag, ikke et døgn, og der er
+	 * ingen tid at læse ud af hvor man slap.
+	 *
+	 * Det var ikke sådan før. Trækket sendte kun datoen, og serveren læser en dato
+	 * uden en tid som "ryd tiden" — så en opgave klokken 14 mistede sit
+	 * klokkeslæt ved at blive flyttet til dagen efter, uden at nogen bad om det.
+	 */
 	async function onDrop(event, date) {
 		event.preventDefault();
 		const id = dragged(event, TASK);
@@ -280,6 +289,44 @@
 		await app.reschedule(id, iso(date));
 	}
 
+	/**
+	 * Sluppet et sted på døgnet: dér, man slap, er klokkeslættet.
+	 *
+	 * Målt mod søjlens egen kasse frem for mod siden, så det bliver rigtigt, uanset
+	 * hvor gitteret sidder, og uanset hvor langt der er rullet.
+	 *
+	 * Rundet til kvarter. Minuttet under markøren er ikke en oplysning, nogen har —
+	 * pegefingeren er bredere end et minut — og 14:07 er et tal, der ser ud som om
+	 * det blev valgt, hvilket er værre end at være omtrentligt.
+	 */
+	async function onDropAt(event, date) {
+		event.preventDefault();
+		const id = dragged(event, TASK);
+		over = null;
+		if (!id) return;
+
+		const box = event.currentTarget.getBoundingClientRect();
+		const share = Math.min(Math.max((event.clientY - box.top) / box.height, 0), 1);
+		const minutes = hours.from * 60 + share * hours.minutes;
+		const snapped = Math.min(Math.round(minutes / 15) * 15, 24 * 60 - 15);
+		await app.reschedule(id, iso(date), clock(snapped));
+	}
+
+	/**
+	 * Sluppet i båndet foroven: opgaven har en dag og ingen tid.
+	 *
+	 * Den tomme streng er ikke det samme som ingenting her — den siger "ryd", hvor
+	 * `undefined` siger "behold". Det er hele grunden til, at de to er skilt ad i
+	 * `reschedule`.
+	 */
+	async function onDropAllDay(event, date) {
+		event.preventDefault();
+		const id = dragged(event, TASK);
+		over = null;
+		if (!id) return;
+		await app.reschedule(id, iso(date), '');
+	}
+
 	// --- ugen som et døgn ---------------------------------------------------------
 	//
 	// En uge, hvor hver dag er en punktopstilling, svarer på "hvad skal der ske
@@ -525,7 +572,7 @@
 						class:over={over === iso(date)}
 						ondragover={(e) => onDragOver(e, date)}
 						ondragleave={() => (over = null)}
-						ondrop={(e) => onDrop(e, date)}
+						ondrop={(e) => onDropAllDay(e, date)}
 					>
 						{#each untimedOn(date) as item (item.kind + item.ref.id)}
 							{#if item.kind === 'event'}
@@ -556,7 +603,7 @@
 						class:over={over === iso(date)}
 						ondragover={(e) => onDragOver(e, date)}
 						ondragleave={() => (over = null)}
-						ondrop={(e) => onDrop(e, date)}
+						ondrop={(e) => onDropAt(e, date)}
 					>
 						{#each Array(hours.count) as _, i}
 							<div class="hourline" style="top:{(i / hours.count) * 100}%"></div>

web/src/lib/components/TaskDetail.svelte

@@ -11,7 +11,7 @@
 	 * necessarily the last one sent.
 	 */
 	import { api, humanMessage } from '$lib/api.js';
-	import { app, projectName } from '$lib/stores.svelte.js';
+	import { app, projectName, clockOf } from '$lib/stores.svelte.js';
 	import { focusOnMount } from '$lib/focus.js';
 	import { t } from '$lib/i18n.svelte.js';
 	import { REPEATS } from '$lib/when.js';
@@ -22,6 +22,7 @@
 	let description = $state('');
 	let priority = $state(4);
 	let dueDate = $state('');
+	let dueTime = $state('');
 	let labels = $state('');
 	let projectId = $state('');
 	let recurrence = $state('');
@@ -55,6 +56,7 @@
 		description = task.description ?? '';
 		priority = task.priority;
 		dueDate = task.due_date ?? '';
+		dueTime = task.due_datetime ? clockOf(task.due_datetime) : '';
 		labels = (task.labels ?? []).join(', ');
 		projectId = task.project_id;
 		recurrence = task.recurrence_rule ?? '';
@@ -407,14 +409,34 @@
 				</select>
 			</div>
 
+			<!--
+				Dato og klokkeslæt gemmes sammen, altid.
+
+				Serveren læser de to felter som ét: kommer datoen uden en tid, *ryddes*
+				tiden. Så et gem af datoen alene tog klokkeslættet med sig — man rettede
+				dagen og mistede timen, uden at noget sagde det.
+
+				Tiden er tom, indtil nogen sætter den. En opgave uden klokkeslæt er det
+				almindelige, og et felt, der åbner på 00:00, er et felt, der påstår, at
+				noget skal ske ved midnat.
+			-->
 			<div class="field">
 				<label for="due">{t('detail.due')}</label>
-				<input
-					id="due"
-					type="date"
-					bind:value={dueDate}
-					onchange={() => save({ due_date: dueDate })}
-				/>
+				<div class="due">
+					<input
+						id="due"
+						type="date"
+						bind:value={dueDate}
+						onchange={() => save({ due_date: dueDate, due_time: dueTime })}
+					/>
+					<input
+						type="time"
+						aria-label={t('detail.dueTime')}
+						bind:value={dueTime}
+						disabled={!dueDate}
+						onchange={() => save({ due_date: dueDate, due_time: dueTime })}
+					/>
+				</div>
 			</div>
 		</div>
 
@@ -692,6 +714,27 @@
 		padding-bottom: max(var(--s8), env(safe-area-inset-bottom));
 	}
 
+	/* Dato og tid på én linje: de er ét svar på ét spørgsmål, og tiden er den
+	   smalle halvdel af det. */
+	.due {
+		display: flex;
+		gap: var(--s2);
+	}
+
+	.due input[type='date'] {
+		flex: 1;
+		min-width: 0;
+	}
+
+	.due input[type='time'] {
+		flex: none;
+		width: 7.5rem;
+	}
+
+	.due input:disabled {
+		opacity: 0.5;
+	}
+
 	.field {
 		display: flex;
 		flex-direction: column;

web/src/lib/locales/da.js

@@ -551,6 +551,7 @@ export const da = {
 	'detail.p1': 'P1 — haster',
 	'detail.none': 'Ingen',
 	'detail.due': 'Forfalder',
+	'detail.dueTime': 'Klokkeslæt',
 	'detail.labels': 'Etiketter',
 	'detail.labelsPlaceholder': 'adskilt af komma',
 	'detail.project': 'Projekt',

web/src/lib/locales/en.js

@@ -547,6 +547,7 @@ export const en = {
 	'detail.p1': 'P1 — urgent',
 	'detail.none': 'None',
 	'detail.due': 'Due',
+	'detail.dueTime': 'Time',
 	'detail.labels': 'Labels',
 	'detail.labelsPlaceholder': 'separated by commas',
 	'detail.project': 'Project',

web/src/lib/stores.svelte.js

@@ -372,10 +372,35 @@ class AppState {
 	}
 
 	/** Puts a task on a day — dropping it on one, in Kommende or in a month grid. */
-	async reschedule(id, date) {
+	/**
+	 * Flytter en opgave til en dag — og afgør, hvad der sker med klokkeslættet.
+	 *
+	 * Serveren læser `due_date` og `due_time` sammen: kommer datoen uden en tid,
+	 * *ryddes* tiden. Det er den rigtige regel for et felt, man skriver i, og den
+	 * forkerte for et træk i en kalender — en opgave, der stod klokken 14, mistede
+	 * sit klokkeslæt ved at blive trukket til dagen efter, uden at nogen bad om
+	 * det, og uden at noget sagde det.
+	 *
+	 * Så tiden siges nu højt, tre måder:
+	 *
+	 *   time === undefined  behold den, opgaven har
+	 *   time === ''         ryd den — det er heldagsbåndet
+	 *   time === 'HH:MM'    sæt den — det er et sted på døgnet
+	 *
+	 * `undefined` og `''` er med vilje to forskellige ting her. De ligner hinanden
+	 * i JavaScript, og det er præcis derfor de skal skilles ad ét sted frem for at
+	 * blive forvekslet fire steder.
+	 */
+	async reschedule(id, date, time) {
 		const previous = this.get(id);
-		if (!previous || previous.due_date === date) return;
-		await this.update(id, { due_date: date });
+		if (!previous) return;
+
+		const clock =
+			time === undefined ? (previous.due_datetime ? clockOf(previous.due_datetime) : '') : time;
+		if (previous.due_date === date && (previous.due_datetime ? clockOf(previous.due_datetime) : '') === clock) {
+			return;
+		}
+		await this.update(id, { due_date: date, due_time: clock });
 	}
 
 	async remove(id) {
@@ -729,6 +754,20 @@ class AppState {
  * Only while it still carries a name the server gave it. Rename it and that is your
  * name for it, in every language — the same rule as any other project.
  */
+/**
+ * Klokkeslættet på en opgave, som "HH:MM" i den maskine, der ser på det.
+ *
+ * `Date` og ikke en strengudskæring: `due_datetime` kommer som UTC med et Z på,
+ * og de fjorten på et stempel er ikke klokken fjorten for den, der læser det.
+ * TaskRow viser tiden på nøjagtig samme måde, og de to steder skal vise det
+ * samme tal.
+ */
+export function clockOf(stamp) {
+	const at = new Date(stamp);
+	if (Number.isNaN(at.getTime())) return '';
+	return `${String(at.getHours()).padStart(2, '0')}:${String(at.getMinutes()).padStart(2, '0')}`;
+}
+
 const SYSTEM_INBOX_NAMES = new Set(['indbakke', 'inbox']);
 
 export function projectName(project) {