feat(notes): første linje er titlen, resten er brødtekst

En ny note åbner på sin titel, og linjen efter er brødtekst — uden at man vælger
noget. Det er det, Apple Notes gør, og det er også hvad listen har brug for:
første linje bliver notens navn, så en note, der begynder i brødtekst, hedder sin
egen første sætning.

To ting undervejs. Reserven for en tom note blev aldrig brugt, fordi en tom tekst
ikke gengives som ingenting men som ét tomt afsnit — den prøves nu på teksten og
ikke på resultatet. Og Chromium svarer på retur med et bart <div>, som læses som
brødtekst men ikke er formateret som det: afstanden mellem afsnit forsvandt
stille i det øjeblik, man trykkede retur frem for at vælge Brødtekst i menuen.

Listen viste desuden den rå Markdown i forhåndsvisningen — "# Møde med Anders" og
"**fed**" — hvilket er præcis det, editoren blev bygget for at holde op med at
vise. Den viser nu sætningen frem for notationen.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/e2e/smoke.spec.js

@@ -2089,3 +2089,43 @@ test('udseendet kan skiftes uafhængigt af temaet, og overlever en genindlæsnin
 
 	expect(trouble).toEqual([]);
 });
+
+test('en ny note begynder som titel, og linjen efter er brødtekst', async ({ page }) => {
+	const trouble = watchForTrouble(page);
+	await page.goto('/noter');
+
+	await page.getByRole('button', { name: 'Ny note' }).click();
+	const ed = page.getByRole('textbox', { name: 'Notens tekst' });
+	await ed.click();
+
+	// Straight in, without choosing a style. The first line is the title because
+	// that is what the list calls the note by.
+	await page.keyboard.type('Titelprøven');
+	await expect(ed.locator('h1')).toHaveText('Titelprøven');
+
+	await page.keyboard.press('Enter');
+	await page.keyboard.type('Han vil gerne have kaffe hver uge.');
+
+	// And the line after is body, not a second title. A note where every line is a
+	// heading is a note with no heading at all.
+	await expect(ed.locator('h1')).toHaveCount(1);
+	await expect(ed.locator('p').filter({ hasText: 'kaffe' })).toBeVisible();
+
+	// A third line stays body too.
+	await page.keyboard.press('Enter');
+	await page.keyboard.type('Og han ringer selv.');
+	await expect(ed.locator('h1')).toHaveCount(1);
+
+	// It survives the trip through Markdown: the title is a heading again on the
+	// way back, and the body is not.
+	await ed.blur();
+	await page.reload();
+	await page.getByRole('button', { name: /Titelprøven/ }).click();
+
+	const back = page.getByRole('textbox', { name: 'Notens tekst' });
+	await expect(back.locator('h1')).toHaveText('Titelprøven');
+	await expect(back.locator('h1')).toHaveCount(1);
+	await expect(back).toContainText('ringer selv');
+
+	expect(trouble).toEqual([]);
+});

web/src/lib/components/NoteEditor.svelte

@@ -29,7 +29,13 @@
 	let loadedId = $state(null);
 	$effect(() => {
 		if (!editor || !note || note.id === loadedId) return;
-		editor.innerHTML = markdownToHtml(note.body) || '<p><br></p>';
+		// An empty note opens on its title. That is what Apple Notes does, and it is
+		// also what the list needs: the first line becomes the name of the note, so a
+		// note whose first line is body text is a note called by its first sentence.
+		//
+		// Tested on the text and not on the rendered result: an empty body renders as
+		// one empty paragraph, not as nothing, so a falsy check here never fired.
+		editor.innerHTML = note.body.trim() ? markdownToHtml(note.body) : '<h1><br></h1>';
 		loadedId = note.id;
 		active = {};
 	});
@@ -92,7 +98,51 @@
 		onchange?.(htmlToMarkdown(editor));
 	}
 
+	/** The block the caret is standing in. */
+	function currentBlock() {
+		const selection = window.getSelection();
+		if (!selection || !selection.anchorNode || !editor) return null;
+		let node = selection.anchorNode;
+		while (node && node.parentNode !== editor) node = node.parentNode;
+		return node?.nodeType === Node.ELEMENT_NODE ? node : null;
+	}
+
+	/**
+	 * Title for the first line, body for everything after it.
+	 *
+	 * Run after the browser has split the block on Enter, because until then there
+	 * is no second block to change. Pressing return at the end of a heading leaves
+	 * the caret in another heading in most browsers, and a note where every line is
+	 * a title is a note with no title at all.
+	 */
+	function keepTitleFirst() {
+		const block = currentBlock();
+		if (!block) return;
+
+		// A heading that is not the first line becomes body.
+		if (block.tagName === 'H1' && block !== editor.firstElementChild) {
+			document.execCommand('formatBlock', false, 'p');
+			return;
+		}
+
+		// And the browser's own container becomes a paragraph. Chromium answers Enter
+		// with a bare <div>, which reads as body but is not styled as one — so the
+		// spacing between paragraphs quietly disappears the moment somebody presses
+		// return rather than choosing Brødtekst from the menu.
+		if (block.tagName === 'DIV') {
+			document.execCommand('formatBlock', false, 'p');
+		}
+	}
+
 	function onkeydown(event) {
+		if (event.key === 'Enter' && !event.shiftKey) {
+			// After the split, not before it.
+			setTimeout(() => {
+				keepTitleFirst();
+				changed();
+			}, 0);
+			return;
+		}
 		// The shortcuts people already have in their fingers. execCommand handles
 		// bold and italic itself; underline and strikethrough are claimed here so
 		// they behave the same way.

web/src/routes/noter/+page.svelte

@@ -48,6 +48,29 @@
 		draft = note?.body ?? '';
 	}
 
+	/**
+	 * The first line or so of a note, without its marks.
+	 *
+	 * The list showed the Markdown as stored — "# Møde med Anders" and "**fed**" —
+	 * which is exactly the thing the editor was built to stop showing. What is
+	 * wanted here is the sentence, not the notation.
+	 */
+	function plain(body) {
+		return (body ?? '')
+			.replace(/^#{1,6}\s+/gm, '')
+			.replace(/^\s*[-*+]\s+/gm, '')
+			.replace(/^\s*>\s?/gm, '')
+			.replace(/\*\*([^*]+)\*\*/g, '$1')
+			.replace(/~~([^~]+)~~/g, '$1')
+			.replace(/<\/?u>/g, '')
+			.replace(/`([^`]+)`/g, '$1')
+			.replace(/\*([^*]+)\*/g, '$1')
+			.replace(/\[\[([^\]]+)\]\]/g, '$1')
+			.replace(/\s+/g, ' ')
+			.trim()
+			.slice(0, 90);
+	}
+
 	async function create() {
 		try {
 			const note = await api.createNote({ body: '' });
@@ -171,7 +194,7 @@
 						<div class="rowline">
 							<button class="row" class:on={selected?.id === note.id} onclick={() => open(note)}>
 								<strong>{note.title || t('notes.untitled')}</strong>
-								<span class="preview">{note.body.slice(0, 80)}</span>
+								<span class="preview">{plain(note.body)}</span>
 							</button>
 							<button
 								class="star"