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

frontend/templates/admin_connections.html

@@ -229,6 +229,18 @@ function openServiceModal(serviceKey) {
           updateDropboxCredentialFieldsVisibility(this.checked);
         });
       }
+      // When the Google "use global credentials" toggle changes, update visibility.
+      if (field.key === 'social_auth_google_use_global_credentials') {
+        checkbox.addEventListener('change', function() {
+          updateGoogleCredentialFieldsVisibility(this.checked);
+        });
+      }
+      // When the Microsoft "use global credentials" toggle changes, update visibility.
+      if (field.key === 'social_auth_microsoft_use_global_credentials') {
+        checkbox.addEventListener('change', function() {
+          updateMicrosoftCredentialFieldsVisibility(this.checked);
+        });
+      }
     } else {
       const input = document.createElement('input');
       input.type = meta.sensitive ? 'password' : 'text';
@@ -266,6 +278,24 @@ function openServiceModal(serviceKey) {
       updateDropboxCredentialFieldsVisibility(isGlobal);
     }
   }
+  // Apply initial visibility for Google credential fields.
+  if (currentServiceKey === 'google') {
+    const useGlobalField = fields.find(function(f) { return f.key === 'social_auth_google_use_global_credentials'; });
+    if (useGlobalField) {
+      const val = useGlobalField.value;
+      const isGlobal = val === true || val === 'true' || val === '1' || val === 'True';
+      updateGoogleCredentialFieldsVisibility(isGlobal);
+    }
+  }
+  // Apply initial visibility for Microsoft credential fields.
+  if (currentServiceKey === 'microsoft') {
+    const useGlobalField = fields.find(function(f) { return f.key === 'social_auth_microsoft_use_global_credentials'; });
+    if (useGlobalField) {
+      const val = useGlobalField.value;
+      const isGlobal = val === true || val === 'true' || val === '1' || val === 'True';
+      updateMicrosoftCredentialFieldsVisibility(isGlobal);
+    }
+  }
 
   modal.classList.remove('hidden');
   // Focus first input
@@ -341,6 +371,28 @@ function updateDropboxCredentialFieldsVisibility(useGlobal) {
   });
 }
 
+// Show or hide the Google client-id / client-secret fields depending on
+// whether the "use global credentials" toggle is enabled.
+function updateGoogleCredentialFieldsVisibility(useGlobal) {
+  ['social_auth_google_client_id', 'social_auth_google_client_secret'].forEach(function(key) {
+    const el = document.querySelector('[data-field-key="' + key + '"]');
+    if (el) {
+      el.style.display = useGlobal ? 'none' : '';
+    }
+  });
+}
+
+// Show or hide the Microsoft client-id / client-secret fields depending on
+// whether the "use global credentials" toggle is enabled.
+function updateMicrosoftCredentialFieldsVisibility(useGlobal) {
+  ['social_auth_microsoft_client_id', 'social_auth_microsoft_client_secret'].forEach(function(key) {
+    const el = document.querySelector('[data-field-key="' + key + '"]');
+    if (el) {
+      el.style.display = useGlobal ? 'none' : '';
+    }
+  });
+}
+
 function toggleSetting(key, value) {
   const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || '';
   fetch('/api/settings/' + key, {