fix(api): add PUT /api/settings/{key} endpoint and shared credentials for Google/Microsoft social login

- Add PUT /{key} endpoint to settings API with SettingValueUpdate body model (only
  requires value, key comes from URL path) — fixes 405 Method Not Allowed errors
  from the admin Connections wizard which used PUT to save settings
- Fix grey toggles on /admin/connections: they appeared grey because all saves were
  silently failing with 405; now saves succeed and toggles reflect actual state
- Add social_auth_google_use_global_credentials config field and auth.py logic to
  reuse google_drive_client_id/google_drive_client_secret for Google Sign-In
- Add social_auth_microsoft_use_global_credentials config field and auth.py logic to
  reuse onedrive_client_id/onedrive_client_secret for Microsoft Sign-In
- Also apply consistent both-field check for Dropbox global credentials fallback
- Add settings metadata entries for the two new boolean settings
- Add Google and Microsoft settings_keys to admin_connections service definitions
- Add JS visibility toggle logic for Google/Microsoft credential fields in admin UI
- Add 6 new unit/integration tests for PUT endpoint and SettingValueUpdate model

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
Agent-Logs-Url: https://github.com/christianlouis/DocuElevate/sessions/ac66041a-2cbd-4d90-8f8e-3588c629d4d8

tests/test_api_settings.py

@@ -180,6 +180,27 @@ class TestSettingModels:
         assert update.key == "test_key"
         assert update.value is None
 
+    def test_setting_value_update_model(self):
+        """Test SettingValueUpdate model (PUT body — no key required)."""
+        from app.api.settings import SettingValueUpdate
+
+        body = SettingValueUpdate(value="test_value")
+        assert body.value == "test_value"
+
+    def test_setting_value_update_model_with_none_value(self):
+        """Test SettingValueUpdate model accepts None value."""
+        from app.api.settings import SettingValueUpdate
+
+        body = SettingValueUpdate(value=None)
+        assert body.value is None
+
+    def test_setting_value_update_model_defaults_to_none(self):
+        """Test SettingValueUpdate model value defaults to None when omitted."""
+        from app.api.settings import SettingValueUpdate
+
+        body = SettingValueUpdate()
+        assert body.value is None
+
     def test_setting_response_model(self):
         """Test SettingResponse model."""
         from app.api.settings import SettingResponse
@@ -205,8 +226,100 @@ class TestSettingModels:
         assert "test_key" in response.db_settings
 
 
-@pytest.mark.unit
-class TestListCredentials:
+@pytest.mark.integration
+class TestPutSettingEndpoint:
+    """Tests for PUT /api/settings/{key} endpoint."""
+
+    def test_put_setting_requires_admin(self, client):
+        """Test PUT /settings/{key} requires admin access."""
+        response = client.put("/api/settings/social_auth_dropbox_enabled", json={"value": "true"})
+        assert response.status_code in [302, 401, 403]
+
+    @patch("app.api.settings.notify_settings_updated")
+    @patch("app.api.settings.get_setting_metadata")
+    @patch("app.api.settings.validate_setting_value")
+    @patch("app.api.settings.save_setting_to_db")
+    def test_put_setting_saves_value(self, mock_save, mock_validate, mock_metadata, mock_notify, client):
+        """Test PUT /settings/{key} saves the value when authenticated as admin."""
+        from app.api.settings import require_admin
+        from app.main import app as fastapi_app
+
+        mock_validate.return_value = (True, None)
+        mock_save.return_value = True
+        mock_metadata.return_value = {"restart_required": True}
+
+        def override_require_admin():
+            return {"id": "admin", "is_admin": True, "preferred_username": "admin"}
+
+        fastapi_app.dependency_overrides[require_admin] = override_require_admin
+        try:
+            response = client.put(
+                "/api/settings/social_auth_dropbox_enabled",
+                json={"value": "true"},
+            )
+            assert response.status_code == 200
+            data = response.json()
+            assert data["success"] is True
+            assert data["key"] == "social_auth_dropbox_enabled"
+            assert data["value"] == "true"
+            assert data["restart_required"] is True
+        finally:
+            fastapi_app.dependency_overrides.pop(require_admin, None)
+
+    @patch("app.api.settings.notify_settings_updated")
+    @patch("app.api.settings.get_setting_metadata")
+    @patch("app.api.settings.validate_setting_value")
+    @patch("app.api.settings.save_setting_to_db")
+    def test_put_setting_body_without_key_field_is_accepted(
+        self, mock_save, mock_validate, mock_metadata, mock_notify, client
+    ):
+        """Test PUT /settings/{key} body need not contain a key field."""
+        from app.api.settings import require_admin
+        from app.main import app as fastapi_app
+
+        mock_validate.return_value = (True, None)
+        mock_save.return_value = True
+        mock_metadata.return_value = {"restart_required": False}
+
+        def override_require_admin():
+            return {"id": "admin", "is_admin": True, "preferred_username": "admin"}
+
+        fastapi_app.dependency_overrides[require_admin] = override_require_admin
+        try:
+            # Body only contains "value" — no "key" field (mirrors admin_connections.html behaviour)
+            response = client.put(
+                "/api/settings/social_auth_dropbox_use_global_credentials",
+                json={"value": "false"},
+            )
+            assert response.status_code == 200
+            data = response.json()
+            assert data["success"] is True
+        finally:
+            fastapi_app.dependency_overrides.pop(require_admin, None)
+
+    @patch("app.api.settings.validate_setting_value")
+    @patch("app.api.settings.get_setting_metadata")
+    def test_put_setting_returns_400_on_invalid_value(self, mock_metadata, mock_validate, client):
+        """Test PUT /settings/{key} returns 400 for invalid values."""
+        from app.api.settings import require_admin
+        from app.main import app as fastapi_app
+
+        mock_validate.return_value = (False, "Invalid boolean value")
+        mock_metadata.return_value = {"restart_required": False}
+
+        def override_require_admin():
+            return {"id": "admin", "is_admin": True}
+
+        fastapi_app.dependency_overrides[require_admin] = override_require_admin
+        try:
+            response = client.put(
+                "/api/settings/social_auth_dropbox_enabled",
+                json={"value": "not_a_bool"},
+            )
+            assert response.status_code == 400
+        finally:
+            fastapi_app.dependency_overrides.pop(require_admin, None)
+
     """Tests for the list_credentials function (GET /api/settings/credentials)."""
 
     @patch("app.api.settings.get_all_settings_from_db")