feat: Phase 6 — require_active_service decorator + wizard install wiring

Email/calendar/files routes now return 404 when the service is not
installed, using a require_active_service decorator that checks
ServiceRegistry. Status endpoints are exempt so health checks always work.

SetupManager.complete_setup() now accepts a service_store_manager and
installs any wizard-selected services in a background daemon thread after
setup completes. Failures are logged but do not fail the wizard.

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

tests/test_file_endpoints.py

@@ -25,12 +25,20 @@ sys.path.insert(0, str(api_dir))
 
 from app import app
 
+_INSTALLED = {'id': 'files', 'installed': True}
+
 
 class TestFileUsersEndpoints(unittest.TestCase):
 
     def setUp(self):
         app.config['TESTING'] = True
         self.client = app.test_client()
+        self._sr_patcher = patch('app.service_registry')
+        mock_sr = self._sr_patcher.start()
+        mock_sr.get.return_value = _INSTALLED
+
+    def tearDown(self):
+        self._sr_patcher.stop()
 
     # ── GET /api/files/users ────────────────────────────────────────────────
 
@@ -94,6 +102,12 @@ class TestFileListEndpoint(unittest.TestCase):
     def setUp(self):
         app.config['TESTING'] = True
         self.client = app.test_client()
+        self._sr_patcher = patch('app.service_registry')
+        mock_sr = self._sr_patcher.start()
+        mock_sr.get.return_value = _INSTALLED
+
+    def tearDown(self):
+        self._sr_patcher.stop()
 
     # ── GET /api/files/list/<username> ─────────────────────────────────────
 
@@ -134,6 +148,12 @@ class TestFileFolderDeleteEndpoint(unittest.TestCase):
     def setUp(self):
         app.config['TESTING'] = True
         self.client = app.test_client()
+        self._sr_patcher = patch('app.service_registry')
+        mock_sr = self._sr_patcher.start()
+        mock_sr.get.return_value = _INSTALLED
+
+    def tearDown(self):
+        self._sr_patcher.stop()
 
     # ── DELETE /api/files/folders/<username>/<path> ────────────────────────
 
@@ -186,6 +206,12 @@ class TestFileDownloadDeleteEndpoints(unittest.TestCase):
     def setUp(self):
         app.config['TESTING'] = True
         self.client = app.test_client()
+        self._sr_patcher = patch('app.service_registry')
+        mock_sr = self._sr_patcher.start()
+        mock_sr.get.return_value = _INSTALLED
+
+    def tearDown(self):
+        self._sr_patcher.stop()
 
     # ── GET /api/files/download/<username>/<path> ──────────────────────────
 
@@ -223,6 +249,12 @@ class TestFileCreateFolderEndpoint(unittest.TestCase):
     def setUp(self):
         app.config['TESTING'] = True
         self.client = app.test_client()
+        self._sr_patcher = patch('app.service_registry')
+        mock_sr = self._sr_patcher.start()
+        mock_sr.get.return_value = _INSTALLED
+
+    def tearDown(self):
+        self._sr_patcher.stop()
 
     # ── POST /api/files/folders ────────────────────────────────────────────
 
@@ -259,6 +291,12 @@ class TestFileUploadEndpoint(unittest.TestCase):
     def setUp(self):
         app.config['TESTING'] = True
         self.client = app.test_client()
+        self._sr_patcher = patch('app.service_registry')
+        mock_sr = self._sr_patcher.start()
+        mock_sr.get.return_value = _INSTALLED
+
+    def tearDown(self):
+        self._sr_patcher.stop()
 
     # ── POST /api/files/upload/<username> ──────────────────────────────────