fix(admin): address PR review feedback from all personas

Blockers resolved:
- localStorage key collision: UsersListPanel/GroupsListPanel/TagsListPanel
  now each use their own key (admin_*_list_collapsed)
- $effect autocollapse replaced with $derived(autocollapse || manualCollapse)
  across all three list panels (Felix — Svelte 5 rule violation)
- groups/new: add READ_ALL and ANNOTATE_ALL to available standard permissions
- Mobile back-to-list links added to all five detail panel headers (md:hidden)
  so users landing directly on a detail URL on mobile can navigate back
- onDestroy(() => stopPolling()) added to system/+page.svelte (Tobias)

High priority resolved:
- Permission labels in groups/[id] and groups/new now use Paraglide i18n keys
  (admin_perm_read_all, admin_perm_annotate_all, etc.) across de/en/es
- $derived used for permission arrays (reactive i18n) — Felix Svelte 5 rule
- UserGroup type in +layout.server.ts now uses generated API type (Markus/Felix)
- discardTarget annotation changed to variable-level type annotation

Accessibility (Leonie):
- EntityNav tablet icon strip buttons: min-h-[44px] for WCAG 2.5.8 compliance
- Flyout focus management: openFlyout() focuses first link, closeFlyout()
  returns focus to the trigger button that opened it
- Flyout animation replaced: broken inline style -> transition:fly={{ x: -160 }}

Tests (Sara/Felix):
- localStorage key assertion tests added per panel
- localStorage.removeItem calls updated to use the panel-specific keys
- page.server.spec.ts added for groups/[id] and tags/[id] delete actions
- Polling lifecycle tests added to system/page.svelte.spec.ts

Note: Paraglide types for new admin_perm_* keys regenerate automatically on
next npm run dev (Vite plugin). No manual compilation step needed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/admin/users/UsersListPanel.svelte

@@ -25,17 +25,15 @@ let {
 } = $props();
 
 let searchQuery = $state('');
-let isCollapsed = $state(
-	typeof localStorage !== 'undefined' && localStorage.getItem('admin_list_collapsed') === 'true'
+let manualCollapse = $state(
+	typeof localStorage !== 'undefined' &&
+		localStorage.getItem('admin_users_list_collapsed') === 'true'
 );
-
-$effect(() => {
-	if (autocollapse) isCollapsed = true;
-});
+const isCollapsed = $derived(autocollapse || manualCollapse);
 
 $effect(() => {
 	if (typeof localStorage !== 'undefined') {
-		localStorage.setItem('admin_list_collapsed', String(isCollapsed));
+		localStorage.setItem('admin_users_list_collapsed', String(manualCollapse));
 	}
 });
 
@@ -53,7 +51,7 @@ const filtered = $derived(
 {#if isCollapsed}
 	<!-- Collapsed handle: 32px -->
 	<button
-		onclick={() => (isCollapsed = false)}
+		onclick={() => (manualCollapse = false)}
 		aria-label={m.admin_btn_expand_list()}
 		class="flex w-8 flex-shrink-0 flex-col items-center gap-2 border-r border-line bg-surface pt-2 hover:bg-muted"
 	>
@@ -93,7 +91,7 @@ const filtered = $derived(
 					</svg>
 				</a>
 				<button
-					onclick={() => (isCollapsed = true)}
+					onclick={() => (manualCollapse = true)}
 					aria-label={m.admin_btn_collapse_list()}
 					class="flex h-6 w-6 items-center justify-center rounded-sm text-xs font-bold text-ink-2 transition-colors hover:bg-muted"
 				>

frontend/src/routes/admin/users/[id]/+page.svelte

@@ -12,7 +12,7 @@ const selectedGroupIds = $derived(data.editUser.groups?.map((g: { id: string })
 
 let isDirty = $state(false);
 let showUnsavedWarning = $state(false);
-let discardTarget = $state<string | null>(null);
+let discardTarget: string | null = $state(null);
 
 beforeNavigate(({ cancel, to }) => {
 	if (isDirty) {
@@ -33,6 +33,21 @@ $effect(() => {
 <div class="flex flex-1 flex-col overflow-hidden">
 	<!-- Detail panel header -->
 	<div class="flex items-center border-b border-line px-5 py-3">
+		<a
+			href="/admin/users"
+			class="mr-3 inline-flex items-center gap-1 text-xs text-ink-3 hover:text-ink md:hidden"
+		>
+			<svg
+				class="h-4 w-4"
+				fill="none"
+				viewBox="0 0 24 24"
+				stroke="currentColor"
+				stroke-width="2"
+				aria-hidden="true"
+			>
+				<path stroke-linecap="round" stroke-linejoin="round" d="M15 19l-7-7 7-7" />
+			</svg>
+		</a>
 		<h2 class="flex-1 font-sans text-sm font-bold text-ink">
 			{m.admin_user_edit_heading({ username: data.editUser.username })}
 		</h2>

frontend/src/routes/admin/users/layout.svelte.spec.ts

@@ -97,7 +97,7 @@ describe('UsersListPanel — empty state', () => {
 // ─── Collapse toggle ──────────────────────────────────────────────────────────
 
 describe('UsersListPanel — collapse toggle', () => {
-	beforeEach(() => localStorage.removeItem('admin_list_collapsed'));
+	beforeEach(() => localStorage.removeItem('admin_users_list_collapsed'));
 
 	it('renders a collapse button with aria-label', async () => {
 		render(UsersListPanel, { users });
@@ -129,4 +129,12 @@ describe('UsersListPanel — collapse toggle', () => {
 			.element(page.getByRole('button', { name: /Liste ausklappen/i }))
 			.toBeInTheDocument();
 	});
+
+	it('persists collapse state using the users-specific localStorage key', async () => {
+		const setSpy = vi.spyOn(Storage.prototype, 'setItem');
+		render(UsersListPanel, { users });
+		document.querySelector<HTMLButtonElement>('[aria-label="Liste einklappen"]')!.click();
+		expect(setSpy).toHaveBeenCalledWith('admin_users_list_collapsed', 'true');
+		setSpy.mockRestore();
+	});
 });

frontend/src/routes/admin/users/new/+page.svelte

@@ -10,7 +10,7 @@ let { data, form } = $props();
 
 let isDirty = $state(false);
 let showUnsavedWarning = $state(false);
-let discardTarget = $state<string | null>(null);
+let discardTarget: string | null = $state(null);
 
 beforeNavigate(({ cancel, to }) => {
 	if (isDirty) {
@@ -24,6 +24,21 @@ beforeNavigate(({ cancel, to }) => {
 <div class="flex flex-1 flex-col overflow-hidden">
 	<!-- Detail panel header -->
 	<div class="flex items-center border-b border-line px-5 py-3">
+		<a
+			href="/admin/users"
+			class="mr-3 inline-flex items-center gap-1 text-xs text-ink-3 hover:text-ink md:hidden"
+		>
+			<svg
+				class="h-4 w-4"
+				fill="none"
+				viewBox="0 0 24 24"
+				stroke="currentColor"
+				stroke-width="2"
+				aria-hidden="true"
+			>
+				<path stroke-linecap="round" stroke-linejoin="round" d="M15 19l-7-7 7-7" />
+			</svg>
+		</a>
 		<h2 class="flex-1 font-sans text-sm font-bold text-ink">{m.admin_user_new_heading()}</h2>
 	</div>