fix(mobile): the project header wraps instead of crushing the title

On a phone, a project called "Skovvænget" rendered as a vertical column of
single letters while the buttons ran off the right edge. It looked like a
broken font.

The header is a flex row of a title and four controls, and 390px does not
have room for them. Nothing wrapped, so the heading was shrunk to its
min-content — which with `overflow-wrap: anywhere` is one character. Adding
Historik this evening is what tipped it over.

It wraps now, and the title keeps a floor of 8ch so flex stops squeezing at
the point where wrapping is the better answer. Kommende had the same shape
and gets the same fix.

Every other smoke test runs at desktop width, which is exactly why this
shipped. There is one at 390 now: it measures the heading's box — wide
enough to hold a word, short enough not to be a column of letters — and
checks the page cannot be scrolled sideways.

Also stops an empty project saying both "Uden sektion" and "Ingenting her
endnu": that label is a heading for the tasks outside a section, and with no
sections there is nothing for them to be outside of.

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

Dockerfile

@@ -5,7 +5,17 @@
 # manager and no libc — the attack surface of the running container is the binary.
 
 # --- 1. the web interface ----------------------------------------------------
-FROM node:22-alpine AS web
+#
+# Pinned to the *build* platform, not the target. What this stage produces is
+# HTML, CSS and JavaScript, which are the same bytes whatever the image will run
+# on — so building it once and copying it into both architectures is not an
+# optimisation, it is the correct thing.
+#
+# Without the pin, buildx runs this stage once per target, which means running
+# Node and esbuild under QEMU for arm64. That crashes: exit 132, SIGILL, an
+# instruction the emulator does not implement, roughly one release in three. It
+# looks like a broken build and is a broken emulator.
+FROM --platform=$BUILDPLATFORM node:22-alpine AS web
 
 WORKDIR /src
 COPY web/ ./
@@ -24,7 +34,12 @@ RUN if [ -f package.json ]; then \
     fi
 
 # --- 2. the binary -----------------------------------------------------------
-FROM golang:1.26-alpine AS build
+#
+# Also pinned to the build platform, and cross-compiled instead. Go does that
+# natively and CGO is already off, so there is nothing to emulate — where
+# building *in* the target architecture means running the whole Go toolchain
+# under QEMU for one of the two.
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine AS build
 
 WORKDIR /src
 
@@ -37,11 +52,13 @@ COPY . .
 COPY --from=web /src/build ./cmd/verdande/webbuild
 
 ARG VERSION=dev
+# Supplied by buildx per target. The default keeps a plain `docker build` working.
+ARG TARGETARCH=amd64
 
 # CGO off is what makes this binary static, and it is only possible because the
 # SQLite driver is pure Go. -trimpath and the empty buildid keep the output
 # reproducible; -s -w drop the symbol and DWARF tables, which is most of the size.
-RUN CGO_ENABLED=0 GOOS=linux go build \
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=${TARGETARCH} go build \
         -tags embedweb \
         -trimpath \
         -ldflags="-s -w -buildid= -X main.version=${VERSION}" \

web/e2e/smoke.spec.js

@@ -804,6 +804,46 @@ test('en rolle kan rettes uden at fjerne personen', async ({ browser, page }) =>
 	expect(trouble).toEqual([]);
 });
 
+/**
+ * The project page on a phone.
+ *
+ * Every other test here runs at desktop width, and this is what that misses: the
+ * header is a flex row of a title and four controls, and 390px does not have room
+ * for them. Without wrapping, the heading was squeezed to its min-content — which
+ * with `overflow-wrap: anywhere` is one character — so a project called
+ * "Skovvænget" rendered as a vertical column of letters while the buttons ran off
+ * the right edge. It looked like a broken font.
+ */
+test('projektsiden er brugbar på en telefon', async ({ page }) => {
+	const trouble = watchForTrouble(page);
+	await page.setViewportSize({ width: 390, height: 844 });
+	await page.goto('/');
+
+	// The sidebar is a drawer at this width, so the project is reached through it.
+	await page.getByRole('button', { name: 'Vis menu' }).click();
+	const sidebar = page.getByRole('navigation', { name: 'Hovedmenu' });
+	await sidebar.getByRole('button', { name: 'Nyt projekt' }).click();
+	await sidebar.getByLabel('Projektnavn').fill('Skovvænget');
+	await sidebar.getByLabel('Projektnavn').press('Enter');
+
+	const heading = page.getByRole('heading', { name: 'Skovvænget' });
+	await expect(heading).toBeVisible();
+
+	const box = await heading.boundingBox();
+	// Wide enough to hold the word, and short enough not to be a column of
+	// letters. One line of "Skovvænget" at --text-2xl is nowhere near 200px tall.
+	expect(box.width, 'overskriften er klemt sammen').toBeGreaterThan(120);
+	expect(box.height, 'overskriften er brudt op i én bogstavkolonne').toBeLessThan(120);
+
+	// And nothing sticks out past the right edge of the page.
+	const overflow = await page.evaluate(
+		() => document.documentElement.scrollWidth - document.documentElement.clientWidth
+	);
+	expect(overflow, 'siden kan scrolles vandret').toBeLessThanOrEqual(1);
+
+	expect(trouble).toEqual([]);
+});
+
 /**
  * The MCP connector address must not fall through to the app shell.
  *

web/src/routes/projekt/[id]/+page.svelte

@@ -548,7 +548,10 @@
 				ondrop={(e) => onSectionDrop(e, '')}
 			>
 				<TaskList tasks={unsectioned} projectId={project.id} sectionId="" {canEdit} />
-				{#if !unsectioned.length}
+				<!-- Only once there are sections to be "without": on a project with none,
+				     the label is a heading for the only list there is, and the empty
+				     state below already says the project is empty. -->
+				{#if sections.length && !unsectioned.length}
 					<p class="empty">Uden sektion</p>
 				{/if}
 			</section>
@@ -664,17 +667,28 @@
 		max-width: 1400px;
 	}
 
+	/* Wraps, and the title keeps a floor.
+	 *
+	 * Without both, a phone squeezes the heading to its min-content — which with
+	 * `overflow-wrap: anywhere` is *one character*, so "Skovvænget" came out as a
+	 * vertical column of letters while the buttons ran off the right edge. Four
+	 * controls beside a title is more than 390px has, so they belong on the next
+	 * line rather than in a race for the same one.
+	 */
 	header {
 		display: flex;
 		align-items: center;
-		gap: var(--s4);
+		gap: var(--s3);
+		flex-wrap: wrap;
 		margin-bottom: var(--s5);
 	}
 
 	h1 {
 		font-size: var(--text-2xl);
-		flex: 1;
+		/* 8ch rather than 0: the basis is what stops flex shrinking it past the
-		min-width: 0;
+		   point where the wrapping below is the better answer. */
+		flex: 1 1 8ch;
+		min-width: 8ch;
 		overflow-wrap: anywhere;
 	}
 
@@ -694,8 +708,8 @@
 
 	/* Matches the heading it stands in for, so the swap does not move the page. */
 	.title {
-		flex: 1;
+		flex: 1 1 8ch;
-		min-width: 0;
+		min-width: 8ch;
 		font-size: var(--text-2xl);
 		font-weight: 560;
 		letter-spacing: -0.015em;

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

@@ -135,17 +135,21 @@
 		max-width: 1400px;
 	}
 
+	/* Wraps, for the same reason the project header does: a title and a switcher
+	   are more than a phone's width, and the switcher belongs underneath rather
+	   than squeezing the heading. */
 	header {
 		display: flex;
 		align-items: center;
-		gap: var(--s4);
+		gap: var(--s3);
+		flex-wrap: wrap;
 		margin-bottom: var(--s5);
 	}
 
 	h1 {
 		font-size: var(--text-2xl);
-		flex: 1;
+		flex: 1 1 8ch;
-		min-width: 0;
+		min-width: 8ch;
 	}
 
 	.views {