feat(tasks): finished work can be looked at, and is out of the way by default

A task list is what is left to do, so closing something has to take it off the
plan. But "what did I get done" is a real question and the answer was nowhere:
once a task was closed it left the interface entirely.

They come back in one list at the bottom rather than back among the open ones in
their sections. A closed task has stopped being work and started being a record,
and putting the record in the middle of the plan makes the plan longer without
making it say more.

Off by default, and deliberately: a list that opens full of things already done is
a list you have to read past before you can use it.

In localStorage rather than on the account, like the sidebar's width and unlike a
folded group. It is a way of *looking*, not a statement about the work — somebody
reviewing their week wants it on for ten minutes, and a setting that followed them
to every device is one they would have to turn off twice.

`loadTasks` asks for closed tasks when the setting is on, rather than each caller
deciding. A view added later cannot then forget and quietly ignore it.

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

web/src/lib/locales/da.js

@@ -583,5 +583,9 @@ export const da = {
 	'push.deniedByBrowser':
 		'Browseren har blokeret notifikationer for dette site. Det skal slås til i browserens indstillinger.',
 	'push.notEnabled': 'Notifikationer blev ikke slået til.',
-	'push.noVapidKey': 'Serveren har ingen VAPID-nøgle.'
+	'push.noVapidKey': 'Serveren har ingen VAPID-nøgle.',
+
+	'view.done': 'Færdige',
+	'view.showDone': 'Vis færdige',
+	'view.hideDone': 'Skjul færdige'
 };

web/src/lib/locales/en.js

@@ -578,5 +578,9 @@ export const en = {
 	'push.deniedByBrowser':
 		'The browser has blocked notifications for this site. It has to be turned on in the browser’s own settings.',
 	'push.notEnabled': 'Notifications were not turned on.',
-	'push.noVapidKey': 'The server has no VAPID key.'
+	'push.noVapidKey': 'The server has no VAPID key.',
+
+	'view.done': 'Done',
+	'view.showDone': 'Show done',
+	'view.hideDone': 'Hide done'
 };

web/src/lib/stores.svelte.js

@@ -192,8 +192,19 @@ class AppState {
 
 	// --- tasks ------------------------------------------------------------------
 
+	/**
+	 * Loads a slice of tasks into the store.
+	 *
+	 * Closed ones come along when the view is showing them — asked for here rather
+	 * than at every call site, so a view added later cannot forget and quietly
+	 * ignore the setting. A caller that genuinely wants only what is open passes
+	 * `completed: 'exclude'`.
+	 */
 	async loadTasks(params) {
-		const { tasks } = await api.listTasks(params);
+		const { tasks } = await api.listTasks({
+			completed: completedView.shown ? 'include' : undefined,
+			...params
+		});
 		this.tasks = tasks;
 		return tasks;
 	}
@@ -661,6 +672,37 @@ function read() {
 
 export const upcomingView = new UpcomingView();
 
+/**
+ * Whether the lists show what has already been finished.
+ *
+ * In localStorage rather than on the account, like the sidebar's width and unlike
+ * a folded group. It is a way of *looking* rather than a statement about the work:
+ * somebody reviewing what they got done this week wants it on for ten minutes, and
+ * a setting that followed them to every device would be a setting they had to turn
+ * off twice.
+ *
+ * Off by default, and deliberately. A task list is what is left to do; a list that
+ * opens full of things already done is a list that has to be read past before it
+ * can be used.
+ */
+class CompletedView {
+	shown = $state(
+		typeof localStorage !== 'undefined' && localStorage.getItem('verdande:completed') === 'show'
+	);
+
+	toggle() {
+		this.shown = !this.shown;
+		try {
+			localStorage.setItem('verdande:completed', this.shown ? 'show' : 'hide');
+		} catch {
+			// Private browsing; the choice simply will not persist.
+		}
+	}
+}
+
+export const completedView = new CompletedView();
+
+
 /**
  * The themes on offer.
  *