feat(workbench): scope TagSelector in SceneHeader + agent auto-infer

The SceneHeader (left side of the workbench homepage) now shows a
TagSelector directly above the template-gallery button. Users can
assign scope tags to the active scene — filtering notes/tasks/contacts/
calendar to only records tagged with those scopes (+ untagged globally
visible).

Auto-inference: when a scene is bound to an agent via viewingAsAgentId
and the scene has no explicit scopeTagIds, the agent's scopeTagIds
are used instead. A small "via Agent" hint appears so the user knows
the scope comes from the binding. Explicitly setting scope tags on the
scene overrides the agent's.

New store methods: setSceneScopeTags + updateScene (both sync the
reactive scene-scope store when the active scene is affected).
patchScene accepts scopeTagIds in its type union.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/mana/apps/web/src/lib/components/workbench/scenes/SceneHeader.svelte

@@ -12,12 +12,40 @@
 	import { workbenchScenesStore } from '$lib/stores/workbench-scenes.svelte';
 	import { Sparkle } from '@mana/shared-icons';
 	import { goto } from '$app/navigation';
+	import { TagSelector, type Tag } from '@mana/shared-ui';
+	import { useAllTags } from '@mana/shared-stores';
+	import { useAgents } from '$lib/data/ai/agents/queries';
 
 	interface Props {
 		scene: WorkbenchScene | null;
 	}
 
 	const { scene }: Props = $props();
+	const allTags = $derived(useAllTags());
+	const agents = $derived(useAgents());
+
+	// Auto-infer scopeTagIds from bound agent if scene has no explicit override
+	const effectiveScopeTagIds = $derived.by(() => {
+		if (!scene) return [];
+		if (scene.scopeTagIds?.length) return scene.scopeTagIds;
+		if (scene.viewingAsAgentId) {
+			const agent = agents.value.find((a) => a.id === scene.viewingAsAgentId);
+			return agent?.scopeTagIds ?? [];
+		}
+		return [];
+	});
+
+	const selectedScopeTags = $derived<Tag[]>(
+		allTags.value.filter((t) => effectiveScopeTagIds.includes(t.id))
+	);
+
+	async function handleScopeChange(tags: Tag[]) {
+		if (!scene) return;
+		const ids = tags.map((t) => t.id);
+		await workbenchScenesStore.updateScene(scene.id, {
+			scopeTagIds: ids.length > 0 ? ids : undefined,
+		});
+	}
 
 	// The seeded default scene is called "Home". Its empty-description
 	// placeholder gets a welcoming line instead of the generic prompt.
@@ -131,6 +159,20 @@
 			onblur={(e) => commitDescription(e.currentTarget, scene.description ?? '')}
 		></p>
 
+		<!-- Scope tags: filter what this scene shows -->
+		<div class="scope-picker">
+			<TagSelector
+				tags={allTags.value}
+				selectedTags={selectedScopeTags}
+				onTagsChange={handleScopeChange}
+				placeholder={effectiveScopeTagIds.length > 0 ? '' : 'Bereiche filtern…'}
+				addTagLabel="Bereich hinzufügen"
+			/>
+			{#if !scene.scopeTagIds?.length && scene.viewingAsAgentId && effectiveScopeTagIds.length > 0}
+				<span class="scope-hint">via Agent</span>
+			{/if}
+		</div>
+
 		<!--
 			Template-Gallery shortcut — persistent discoverability hook
 			directly on the homepage. Small chip-style, deliberately
@@ -222,6 +264,18 @@
 		pointer-events: none;
 	}
 
+	.scope-picker {
+		display: flex;
+		align-items: center;
+		gap: 0.5rem;
+		margin-top: 0.25rem;
+	}
+	.scope-hint {
+		font-size: 0.6875rem;
+		color: hsl(var(--color-muted-foreground));
+		font-style: italic;
+		white-space: nowrap;
+	}
 	.template-shortcut {
 		align-self: flex-start;
 		margin-top: 0.75rem;

apps/mana/apps/web/src/lib/stores/workbench-scenes.svelte.ts

@@ -102,7 +102,13 @@ async function patchScene(
 	patch: Partial<
 		Pick<
 			LocalWorkbenchScene,
-			'name' | 'description' | 'openApps' | 'order' | 'wallpaper' | 'viewingAsAgentId'
+			| 'name'
+			| 'description'
+			| 'openApps'
+			| 'order'
+			| 'wallpaper'
+			| 'viewingAsAgentId'
+			| 'scopeTagIds'
 		>
 	>
 ) {
@@ -237,6 +243,21 @@ export const workbenchScenesStore = {
 		await patchScene(id, { viewingAsAgentId: agentId });
 	},
 
+	async setSceneScopeTags(id: string, scopeTagIds: string[] | undefined) {
+		await patchScene(id, { scopeTagIds });
+		// Sync reactive scope if this is the active scene
+		if (id === activeSceneIdState) {
+			setSceneScopeTagIds(scopeTagIds);
+		}
+	},
+
+	async updateScene(id: string, patch: Partial<WorkbenchScene>) {
+		await patchScene(id, patch);
+		if (id === activeSceneIdState && patch.scopeTagIds !== undefined) {
+			setSceneScopeTagIds(patch.scopeTagIds);
+		}
+	},
+
 	async duplicateScene(id: string) {
 		const src = scenesState.find((s) => s.id === id);
 		if (!src) return;