feat(writing): agent.defaultWritingStyleId — M8 persona-linkage follow-up

Agents can now pin a default writing style. When an AI-actor runs
`create_draft` without an explicit styleId, the tool resolves to the
agent's `defaultWritingStyleId` so e.g. a "Marketing-Agent" always
drafts in the Corporate-Tone style and a "Memoir-Agent" in Memoir.

- @mana/shared-ai: optional `defaultWritingStyleId?: string` added to
  the Agent interface (plaintext FK, format `preset:<id>` or a custom
  WritingStyle uuid). No migration — existing rows stay undefined and
  the fallback path no-ops for them.
- ai-agents store: field threaded through CreateAgentInput + AgentPatch
  + the create function's copy-list. `updateAgent` already deep-clones
  the patch so nothing else to change there.
- ai-agents ListView: new "Writing" section in the agent detail panel
  with a StylePicker (reuses the writing module's component — Vorlagen
  + Meine Stile optgroups). Empty = kein Default.
- writing/tools.ts: `resolveAgentDefaultStyle()` reads the current
  actor, guards `isAiActor`, loads the agent row, and returns its
  defaultWritingStyleId. Wired into `create_draft` as a fallback when
  `params.styleId` is missing. User-invoked calls skip the lookup — a
  human omitting styleId means "ad-hoc, no style", not "my default".
  `generate_draft_content` needs no change because the draft's styleId
  is already set at create time.

107 shared-ai tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/mana/apps/web/src/lib/data/ai/agents/store.ts

@@ -40,6 +40,8 @@ export interface CreateAgentInput {
 	policy?: AiPolicy;
 	maxTokensPerDay?: number;
 	maxConcurrentMissions?: number;
+	scopeTagIds?: string[];
+	defaultWritingStyleId?: string;
 	state?: AgentState;
 }
 
@@ -66,6 +68,8 @@ export async function createAgent(input: CreateAgentInput): Promise<Agent> {
 		avatar: input.avatar,
 		systemPrompt: input.systemPrompt,
 		memory: input.memory,
+		scopeTagIds: input.scopeTagIds,
+		defaultWritingStyleId: input.defaultWritingStyleId,
 		policy: deepClone(input.policy ?? DEFAULT_AI_POLICY),
 		maxTokensPerDay: input.maxTokensPerDay,
 		maxConcurrentMissions: input.maxConcurrentMissions ?? 1,
@@ -130,6 +134,7 @@ export interface AgentPatch {
 	maxTokensPerDay?: number;
 	maxConcurrentMissions?: number;
 	scopeTagIds?: string[];
+	defaultWritingStyleId?: string;
 	state?: AgentState;
 }
 

apps/mana/apps/web/src/lib/modules/ai-agents/ListView.svelte

@@ -37,6 +37,7 @@
 	import type { AiPolicy, PolicyDecision } from '@mana/shared-ai';
 	import { TagSelector } from '@mana/shared-ui';
 	import { useAllTags } from '@mana/shared-stores';
+	import StylePicker from '$lib/modules/writing/components/StylePicker.svelte';
 
 	const agents = $derived(useAgents());
 	const allTags = $derived(useAllTags());
@@ -89,6 +90,7 @@
 	let editMaxConcurrent = $state(1);
 	let editMaxTokensPerDay = $state<number | null>(null);
 	let editScopeTagIds = $state<string[]>([]);
+	let editDefaultWritingStyleId = $state<string | null>(null);
 	let lastSyncedId = $state<string | null>(null);
 	let saveError = $state<string | null>(null);
 	let saving = $state(false);
@@ -103,6 +105,7 @@
 			editMaxConcurrent = selected.maxConcurrentMissions;
 			editMaxTokensPerDay = selected.maxTokensPerDay ?? null;
 			editScopeTagIds = [...(selected.scopeTagIds ?? [])];
+			editDefaultWritingStyleId = selected.defaultWritingStyleId ?? null;
 			lastSyncedId = selected.id;
 			saveError = null;
 		}
@@ -121,6 +124,7 @@
 				maxConcurrentMissions: editMaxConcurrent,
 				maxTokensPerDay: editMaxTokensPerDay ?? undefined,
 				scopeTagIds: editScopeTagIds.length > 0 ? editScopeTagIds : undefined,
+				defaultWritingStyleId: editDefaultWritingStyleId ?? undefined,
 			});
 		} catch (err) {
 			if (err instanceof DuplicateAgentNameError) {
@@ -455,6 +459,18 @@
 			</label>
 		</section>
 
+		<section class="block">
+			<h3>Writing</h3>
+			<p class="hint">
+				Default-Schreibstil, den der Agent beim Anlegen eines Drafts nutzt, wenn keiner explizit
+				übergeben wird.
+			</p>
+			<StylePicker
+				value={editDefaultWritingStyleId}
+				onchange={(next) => (editDefaultWritingStyleId = next)}
+			/>
+		</section>
+
 		<div class="save-row">
 			{#if saveError}
 				<span class="form-error">{saveError}</span>

apps/mana/apps/web/src/lib/modules/writing/tools.ts

@@ -27,6 +27,8 @@ import { decryptRecords, VaultLockedError } from '$lib/data/crypto';
 import { toDraft, toDraftVersion } from './queries';
 import { STYLE_PRESETS } from './presets/styles';
 import { writingStyleTable } from './collections';
+import { getCurrentActor, isAiActor } from '$lib/data/events';
+import { getAgent } from '$lib/data/ai/agents/store';
 import type {
 	LocalDraft,
 	LocalDraftVersion,
@@ -35,6 +37,23 @@ import type {
 	DraftStatus,
 } from './types';
 
+/**
+ * When an AI actor is running a writing tool without an explicit
+ * styleId, fall back to the agent's `defaultWritingStyleId`. User-
+ * invoked calls skip this — a human passing no styleId means "ad-hoc,
+ * no style", not "use my default".
+ */
+async function resolveAgentDefaultStyle(): Promise<string | null> {
+	const actor = getCurrentActor();
+	if (!isAiActor(actor)) return null;
+	try {
+		const agent = await getAgent(actor.principalId);
+		return agent?.defaultWritingStyleId ?? null;
+	} catch {
+		return null;
+	}
+}
+
 const KINDS: DraftKind[] = [
 	'blog',
 	'essay',
@@ -266,11 +285,16 @@ export const writingTools: ModuleTool[] = [
 
 			const targetWordsRaw =
 				typeof params.targetWords === 'number' ? Math.round(params.targetWords) : null;
+			const explicitStyleId =
+				typeof params.styleId === 'string' && params.styleId.length > 0 ? params.styleId : null;
+			// Persona-Linkage: AI actors inherit the agent's default style
+			// when they don't pass one; user-invoked calls do not — a human
+			// omitting styleId means "ad-hoc, no style".
+			const styleId = explicitStyleId ?? (await resolveAgentDefaultStyle());
 			const { draft } = await draftsStore.createDraft({
 				kind,
 				title,
-				styleId:
-					typeof params.styleId === 'string' && params.styleId.length > 0 ? params.styleId : null,
+				styleId,
 				briefing: {
 					topic,
 					audience: typeof params.audience === 'string' ? params.audience : null,