feat(M6): Weitere Hosts — MiniApps in Fenstern + AI-Agenten-Ausgabe-Bloecke (#364)

- Windows-Host: openMiniAppWindow-Helper + MiniAppWindowContent (windowStore);
  Oeffnen-Buttons im Chat-Block (MiniAppBlock) und Dashboard-Widget
- AI-Agenten-Host: Core-Tool send_miniapp (app/ai/miniapp_tools.py) —
  miniapp-Block in Agent-Chat (approval_request-Praezedenz), Permission
  fail-closed gegen aufrufenden User pro App; Registrierung im lifespan
- agent_loop: tool_context + agent_name (Raum-Aufloesung)
- Fix: MiniAppBlock nutzt useMiniapps (component-Feld) statt Legacy /comm/miniapps
- Tests: M6 7/7 (TDD rot->gruen), Backend-Regression 57/57, Vitest 26/26
  (4 neue Window-Tests), tsc clean, build OK

frontend/src/__tests__/dashboard/MiniAppWindow.test.tsx

@@ -0,0 +1,103 @@
+import React from 'react';
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { MiniAppWindowContent } from '@/components/dashboard/MiniAppWindowContent';
+import { openMiniAppWindow } from '@/components/dashboard/openMiniAppWindow';
+import { useWindowStore } from '@/store/windowStore';
+
+/**
+ * M6 — Windows host tests: MiniApps open in floating windows via the
+ * existing window manager (openMiniAppWindow + MiniAppWindowContent).
+ */
+
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: (key: string) => key }),
+}));
+
+vi.mock('@/api/miniapps', () => ({
+  useMiniapps: () => ({
+    data: {
+      items: [
+        {
+          app_id: 'recent_contacts', name: 'Recent Contacts', icon: 'Users', description: 'desc',
+          plugin_name: 'contacts', render_schema: {}, permission: '', settings_schema: {},
+          col_span: 2, row_span: 1, hosts: ['chat', 'dashboard', 'window'],
+          component: '@/components/dashboard/RecentContactsWidget', order: 10, builtin: true,
+        },
+      ],
+      total: 1,
+    },
+    isLoading: false,
+  }),
+}));
+
+vi.mock('@/components/dashboard/MiniAppHost', () => ({
+  MiniAppHost: ({ appId }: { appId: string }) => (
+    <div data-testid={`miniapp-${appId}`}>host:{appId}</div>
+  ),
+}));
+
+const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+
+function renderContent() {
+  return render(
+    <QueryClientProvider client={queryClient}>
+      <MiniAppWindowContent appId="recent_contacts" settings={{ limit: 5 }} />
+    </QueryClientProvider>
+  );
+}
+
+describe('MiniAppWindowContent', () => {
+  it('renders the MiniApp host with the given app id', () => {
+    renderContent();
+    expect(screen.getByTestId('miniapp-window-recent_contacts')).toBeInTheDocument();
+    expect(screen.getByTestId('miniapp-recent_contacts')).toBeInTheDocument();
+  });
+
+  it('shows the app description when present', () => {
+    renderContent();
+    expect(screen.getByText('desc')).toBeInTheDocument();
+  });
+});
+
+describe('openMiniAppWindow', () => {
+  it('opens a window with miniapp type and props', () => {
+    const spy = vi.fn();
+    // spy on the store's openWindow implementation
+    const state = useWindowStore.getState();
+    const origOpen = state.openWindow;
+    useWindowStore.setState({ openWindow: spy as never });
+
+    openMiniAppWindow({
+      appId: 'recent_contacts',
+      settings: { limit: 3 },
+      component: MiniAppWindowContent as never,
+    });
+
+    expect(spy).toHaveBeenCalledTimes(1);
+    const config = spy.mock.calls[0][0];
+    expect(config.type).toBe('miniapp-recent_contacts');
+    expect(config.title).toBe('recent_contacts');
+    expect(config.componentProps).toEqual({ appId: 'recent_contacts', settings: { limit: 3 } });
+
+    // restore
+    useWindowStore.setState({ openWindow: origOpen as never, windows: [] });
+  });
+
+  it('uses the def name as window title when provided', () => {
+    const spy = vi.fn();
+    const state = useWindowStore.getState();
+    const origOpen = state.openWindow;
+    useWindowStore.setState({ openWindow: spy as never });
+
+    openMiniAppWindow({
+      appId: 'x',
+      def: { name: 'Mein Widget' } as never,
+      component: MiniAppWindowContent as never,
+    });
+
+    expect(spy.mock.calls[0][0].title).toBe('Mein Widget');
+    useWindowStore.setState({ openWindow: origOpen as never, windows: [] });
+  });
+});

frontend/src/components/comm/blocks/MiniAppBlock.tsx

@@ -1,42 +1,36 @@
-import React, { useState, useEffect } from 'react';
+import React from 'react';
+import { useTranslation } from 'react-i18next';
 import type { MessageBlock } from '@/store/commStore';
-import { AppWindow, Loader2 } from 'lucide-react';
-import { apiClient } from '@/api/client';
+import { AppWindow, ExternalLink, Loader2 } from 'lucide-react';
+import { useMiniapps, type MiniAppDef } from '@/api/miniapps';
+import { MiniAppWindowContent } from '@/components/dashboard/MiniAppWindowContent';
+import { openMiniAppWindow } from '@/components/dashboard/openMiniAppWindow';
 
 interface MiniAppBlockProps {
   block: MessageBlock;
 }
 
-interface MiniAppDef {
-  app_id: string;
-  name: string;
-  icon: string;
-  description: string;
-  plugin_name: string;
-  render_schema: Record<string, any>;
-}
-
 const MiniAppBlock: React.FC<MiniAppBlockProps> = ({ block }) => {
+  const { t } = useTranslation();
   const { app_id, config } = block.block_data;
-  const [appDef, setAppDef] = useState<MiniAppDef | null>(null);
-  const [loading, setLoading] = useState(false);
+  // M6: universal registry endpoint (carries component/permission fields;
+  // the legacy /comm/miniapps list never did, hiding the window button)
+  const { data: miniappsData, isLoading: loading } = useMiniapps();
+  const appDef: MiniAppDef | null =
+    miniappsData?.items.find((a) => a.app_id === app_id) ?? null;
 
-  useEffect(() => {
-    if (!app_id) return;
-    setLoading(true);
-    apiClient.get('/comm/miniapps')
-      .then((res) => {
-        const apps: MiniAppDef[] = res.data || [];
-        const found = apps.find((a) => a.app_id === app_id);
-        setAppDef(found || null);
-      })
-      .catch(() => setAppDef(null))
-      .finally(() => setLoading(false));
-  }, [app_id]);
+  const canOpenInWindow = Boolean(appDef?.component);
+  const openInWindow = () =>
+    openMiniAppWindow({
+      appId: app_id || '',
+      def: appDef ?? undefined,
+      settings: (config as Record<string, unknown>) ?? {},
+      component: MiniAppWindowContent,
+    });
 
   const appId: string = app_id || 'Unbekannt';
   const hasConfig = config && typeof config === 'object' && Object.keys(config).length > 0;
-  const schema = appDef?.render_schema;
+  const schema = appDef?.render_schema as { fields?: { name: string; label?: string }[] } | undefined;
   const hasSchema = schema && Object.keys(schema).length > 0;
 
   if (loading) {
@@ -60,6 +54,18 @@ const MiniAppBlock: React.FC<MiniAppBlockProps> = ({ block }) => {
         {appDef?.plugin_name && (
           <span className="text-xs px-2 py-0.5 rounded-full bg-secondary-100 text-secondary-600">{appDef.plugin_name}</span>
         )}
+        {canOpenInWindow && (
+          <button
+            type="button"
+            onClick={openInWindow}
+            className="p-1.5 rounded hover:bg-secondary-100 text-secondary-400 hover:text-primary-600"
+            aria-label={t('dashboard.openInWindow')}
+            title={t('dashboard.openInWindow')}
+            data-testid={`miniapp-open-window-${app_id}`}
+          >
+            <ExternalLink className="w-4 h-4" aria-hidden="true" />
+          </button>
+        )}
       </div>
 
       {hasSchema && schema.fields && (

frontend/src/components/dashboard/DashboardBuilder.tsx

@@ -28,6 +28,7 @@ import {
 } from '@dnd-kit/sortable';
 import { CSS } from '@dnd-kit/utilities';
 import {
+  ExternalLink,
   LayoutDashboard,
   Pencil,
   Check,
@@ -56,6 +57,8 @@ import {
 } from '@/api/dashboards';
 import { useMiniapps, renderableDashboardApps, type MiniAppDef } from '@/api/miniapps';
 import { MiniAppHost } from './MiniAppHost';
+import { MiniAppWindowContent } from './MiniAppWindowContent';
+import { openMiniAppWindow } from './openMiniAppWindow';
 import { WidgetSettingsForm } from './WidgetSettingsForm';
 
 let widgetIdCounter = 0;
@@ -166,6 +169,22 @@ function SortableWidget({ widget, def, editMode, onRemove, onResize, onOpenSetti
             >
               <Plus className="w-3.5 h-3.5 rotate-90" aria-hidden="true" />
             </button>
+            <button
+              type="button"
+              onClick={() =>
+                openMiniAppWindow({
+                  appId: widget.app_id,
+                  def,
+                  settings: widget.settings,
+                  component: MiniAppWindowContent,
+                })
+              }
+              className="p-1.5 rounded hover:bg-secondary-100 text-secondary-500"
+              aria-label={t('dashboard.openInWindow')}
+              data-testid="dashboard-widget-open-window"
+            >
+              <ExternalLink className="w-3.5 h-3.5" aria-hidden="true" />
+            </button>
             <button
               type="button"
               onClick={onOpenSettings}

frontend/src/components/dashboard/MiniAppWindowContent.tsx

@@ -0,0 +1,38 @@
+/**
+ * MiniAppWindowContent — window host for a MiniApp (Phase M6).
+ *
+ * Rendered inside the window manager's floating windows: resolves the
+ * MiniApp definition (name, settings_schema) and renders the shared
+ * MiniAppHost as the window body.
+ */
+
+import React from 'react';
+import { useTranslation } from 'react-i18next';
+import { useMiniapps } from '@/api/miniapps';
+import { MiniAppHost } from '@/components/dashboard/MiniAppHost';
+
+export interface MiniAppWindowContentProps {
+  appId: string;
+  settings?: Record<string, unknown>;
+}
+
+export function MiniAppWindowContent({ appId, settings }: MiniAppWindowContentProps) {
+  const { t } = useTranslation();
+  const { data, isLoading } = useMiniapps();
+  const def = data?.items.find((a) => a.app_id === appId);
+
+  return (
+    <div className="p-4 h-full overflow-auto" data-testid={`miniapp-window-${appId}`}>
+      {isLoading ? (
+        <p className="text-sm text-secondary-500">{t('common.loading', 'Lädt…')}</p>
+      ) : (
+        <>
+          {def?.description && (
+            <p className="text-xs text-secondary-400 mb-3">{def.description}</p>
+          )}
+          <MiniAppHost appId={appId} settings={settings ?? {}} def={def} />
+        </>
+      )}
+    </div>
+  );
+}

frontend/src/components/dashboard/openMiniAppWindow.ts

@@ -0,0 +1,37 @@
+/**
+ * openMiniAppWindow — open a MiniApp in a floating window (Phase M6).
+ *
+ * Windows host: any inline MiniApp (chat block, dashboard widget) can be
+ * popped into a draggable window via the existing window manager.
+ */
+
+import type { ComponentType } from 'react';
+import { useWindowStore } from '@/store/windowStore';
+import type { MiniAppDef } from '@/api/miniapps';
+
+export interface OpenMiniAppWindowOptions {
+  appId: string;
+  title?: string;
+  settings?: Record<string, unknown>;
+  def?: MiniAppDef;
+  component: ComponentType<{ appId: string; settings?: Record<string, unknown> }>;
+  width?: number;
+  height?: number;
+}
+
+export function openMiniAppWindow(opts: OpenMiniAppWindowOptions): string {
+  const store = useWindowStore.getState();
+  const title = opts.title ?? opts.def?.name ?? opts.appId;
+  const id = store.openWindow({
+    title,
+    type: `miniapp-${opts.appId}`,
+    component: opts.component,
+    componentProps: {
+      appId: opts.appId,
+      settings: opts.settings ?? {},
+    },
+  });
+  // openWindow applies the default size; MiniApps get a compact default
+  store.updateWindowSize(id, { width: opts.width ?? 520, height: opts.height ?? 480 });
+  return id;
+}

frontend/src/i18n/locales/de.json

@@ -163,7 +163,8 @@
       "taller": "Höher",
       "shorter": "Niedriger"
     },
-    "systemMetricsNoAccess": "Systemmetriken erfordern Admin-Rechte."
+    "systemMetricsNoAccess": "Systemmetriken erfordern Admin-Rechte.",
+    "openInWindow": "In Fenster öffnen"
   },
   "companies": {
     "title": "Firmen",

frontend/src/i18n/locales/en.json

@@ -163,7 +163,8 @@
       "taller": "Taller",
       "shorter": "Shorter"
     },
-    "systemMetricsNoAccess": "System metrics require admin rights."
+    "systemMetricsNoAccess": "System metrics require admin rights.",
+    "openInWindow": "Open in window"
   },
   "companies": {
     "title": "Companies",