Add PDF document service with AI extraction and per-app settings

- New `features/doc-service` FastAPI microservice: PDF upload, async
  text extraction (pdfplumber), AI classification via Anthropic/Ollama/
  LM Studio, per-user categories, file download
- Alembic migration isolated with `alembic_version_doc_service` table
- Main backend: httpx proxy routers for /api/documents/* and
  /api/documents/categories/*, admin settings API at /api/settings/*
- Runtime config in /config/doc_service_config.json (shared Docker
  volume); api_key masking on reads; atomic write with os.replace()
- Frontend: DocumentsPage, DocumentAdminSettingsPage, updated AppsPage
  launcher hub, simplified Nav (removed Settings link), new routes
- docker-compose: doc-service service, doc_data + app_config volumes,
  removed internal:true from backend-net for outbound AI API calls
- Fix pre-commit hook: probe Docker socket path so git subprocess picks
  up Docker Desktop on macOS
- Fix security_check.py: use sys.executable for bandit so venv python
  is used instead of system python

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

frontend/src/App.tsx

@@ -6,8 +6,9 @@ import LoginPage from "./pages/LoginPage";
 import DashboardPage from "./pages/DashboardPage";
 import ProfilePage from "./pages/ProfilePage";
 import AppsPage from "./pages/AppsPage";
-import SettingsPage from "./pages/SettingsPage";
 import AdminPage from "./pages/AdminPage";
+import DocumentsPage from "./pages/DocumentsPage";
+import DocumentAdminSettingsPage from "./pages/DocumentAdminSettingsPage";
 
 function PrivateRoute({ children }: { children: React.ReactNode }) {
   const { token } = useAuth();
@@ -33,7 +34,11 @@ export default function App() {
 
       <Route path="/" element={<PrivateRoute><DashboardPage /></PrivateRoute>} />
       <Route path="/apps" element={<PrivateRoute><AppsPage /></PrivateRoute>} />
-      <Route path="/settings" element={<PrivateRoute><SettingsPage /></PrivateRoute>} />
+      <Route path="/apps/documents" element={<PrivateRoute><DocumentsPage /></PrivateRoute>} />
+      <Route
+        path="/apps/documents/settings/admin"
+        element={<AdminRoute><DocumentAdminSettingsPage /></AdminRoute>}
+      />
       <Route path="/profile" element={<PrivateRoute><ProfilePage /></PrivateRoute>} />
       <Route path="/admin" element={<AdminRoute><AdminPage /></AdminRoute>} />