feat(ui): External-Agent-API + Besitzübertragung UI (UI-Backlog Module 15+16/16)

Modul 15 External-Agent (ai_assistant-Plugin, Manifest settings_page):
- SettingsExternalAgents.tsx: Agentenliste mit curl-Snippets (run/status/stream),
  Copy-Buttons, Bearer-Token-Hinweis, Rate-Limit-Doku, Token-Link
- api/externalAgent.ts (useAiAgents, buildCurlSnippets, curlCommand)
- Manifest: settings_pages +external-agents (order 61, permission ai:read)
- Komponenten-Map regeneriert (43)

Modul 16 Ownership-Transfer (Core):
- SettingsOwnership.tsx: Admin-Gate, From/To-User-Selects, 10 Entity-Type-Chips,
  ConfirmDialog, Ergebnis-Tabelle
- api/ownership.ts (useTransferOwnership, OWNERSHIP_ENTITY_TYPES)
- Route /settings/ownership + Nav-Eintrag

i18n de/en +28 Keys. Vitest 12/12, tsc 0, Build OK, ruff OK, Manifest-Import OK

frontend/src/api/externalAgent.ts

@@ -0,0 +1,74 @@
+/**
+ * External Agent API integration client (UI-Backlog module 15/16).
+ *
+ * Backend: /api/v1/external/agent (ai_assistant plugin, external_api.py).
+ * - POST /{agent_id}/run    → run agent, return full response (Bearer auth)
+ * - GET  /{agent_id}/status → agent config + run stats (Bearer auth)
+ * - POST /{agent_id}/stream → SSE stream response (Bearer auth)
+ *
+ * These endpoints are Bearer-token-only (no session cookies) — they are
+ * meant for EXTERNAL systems, not the SPA itself. The UI is therefore an
+ * integration page: it lists the tenant's AI agents (via the existing
+ * /ai/agents endpoint) and renders copy-paste curl snippets per agent.
+ */
+
+import { useQuery } from '@tanstack/react-query';
+import { fetchAgents, type AIAgent } from '@/api/ai';
+
+/** TanStack wrapper around the existing fetchAgents (session auth). */
+export function useAiAgents() {
+  return useQuery({
+    queryKey: ['ai-agents'],
+    queryFn: () => fetchAgents(),
+  });
+}
+
+export interface CurlSnippet {
+  method: 'POST' | 'GET';
+  endpoint: string;
+  body?: string;
+  description: string;
+}
+
+/** Base URL of this deployment (works for prod and local dev). */
+export function externalBaseUrl(): string {
+  return `${window.location.origin}/api/v1/external/agent`;
+}
+
+/** Build the copy-paste curl examples for one agent. */
+export function buildCurlSnippets(agentId: string): CurlSnippet[] {
+  const base = externalBaseUrl();
+  return [
+    {
+      method: 'POST',
+      endpoint: `${base}/${agentId}/run`,
+      body: JSON.stringify({ message: 'Hello, summarize my open tasks' }),
+      description: 'runAgent',
+    },
+    {
+      method: 'GET',
+      endpoint: `${base}/${agentId}/status`,
+      description: 'getStatus',
+    },
+    {
+      method: 'POST',
+      endpoint: `${base}/${agentId}/stream`,
+      body: JSON.stringify({ message: 'Hello, stream me an answer' }),
+      description: 'streamAgent (SSE)',
+    },
+  ];
+}
+
+/** Render a single-line curl command for a snippet. */
+export function curlCommand(snippet: CurlSnippet): string {
+  const parts: string[] = [];
+  parts.push(`curl -X ${snippet.method} '${snippet.endpoint}'`);
+  parts.push(`-H 'Authorization: Bearer <API_TOKEN>'`);
+  if (snippet.body) {
+    parts.push(`-H 'Content-Type: application/json'`);
+    parts.push(`-d '${snippet.body}'`);
+  }
+  return parts.join(' ');
+}
+
+export type { AIAgent };

frontend/src/api/ownership.ts

@@ -0,0 +1,46 @@
+/**
+ * Ownership transfer API client (UI-Backlog module 16/16).
+ *
+ * Backend: /api/v1/ownership (app/routes/owner_transfer.py, require_admin).
+ * - POST /transfer → bulk-transfer records from one user to another
+ *
+ * Entity types: contacts, addresses, attachments, bank_accounts,
+ * workflows, sequences, saved_filters, saved_views, webhooks,
+ * notifications (mirrored from owner_transfer_service.ENTITY_TABLES).
+ */
+
+import { useMutation } from '@tanstack/react-query';
+import { apiPost } from '@/api/client';
+
+export const OWNERSHIP_ENTITY_TYPES = [
+  'contacts',
+  'addresses',
+  'attachments',
+  'bank_accounts',
+  'workflows',
+  'sequences',
+  'saved_filters',
+  'saved_views',
+  'webhooks',
+  'notifications',
+] as const;
+
+export type OwnershipEntityType = (typeof OWNERSHIP_ENTITY_TYPES)[number];
+
+export interface OwnershipTransferPayload {
+  from_user_id: string;
+  to_user_id: string;
+  entity_types?: string[] | null;
+}
+
+export interface OwnershipTransferResult {
+  message: string;
+  results: Record<string, number>;
+}
+
+export function useTransferOwnership() {
+  return useMutation({
+    mutationFn: (data: OwnershipTransferPayload) =>
+      apiPost<OwnershipTransferResult>('/ownership/transfer', data),
+  });
+}