Customised Analytics for admins and users (#4687)

Adds granular privacy controls for analytics - splits single
enableAnalytics toggle into separate PostHog and Scarf controls with
improved admin
  UX.

  Backend Changes

  Configuration (ApplicationProperties.java)
  - Added enablePosthog and enableScarf boolean fields
- New methods: isPosthogEnabled(), isScarfEnabled() (null = enabled when
analytics is on)

  Services
- PostHogService: Now checks isPosthogEnabled() instead of
isAnalyticsEnabled()
  - ConfigController: Exposes new flags via API
- SettingsController: Changed endpoint from @RequestBody to
@RequestParam

  Frontend Changes

  Architecture
- Converted useAppConfig hook → AppConfigContext provider for global
access
  - Added refetch() method for config updates without reload

  New Features
1. AdminAnalyticsChoiceModal: First-launch modal when enableAnalytics
=== null
    - Enable/disable without editing YAML
    - Includes documentation link
  2. Scarf Tracking System: Modular utility with React hook wrapper
    - Respects config + per-service cookie consent
    - Works from any code location (React or vanilla JS)
3. Enhanced Cookie Consent: Per-service toggles (PostHog and Scarf
separate)

  Integration
  - App.tsx: Added AppConfigProvider + scarf initializer
  - HomePage.tsx: Shows admin modal when needed
  - index.tsx: PostHog opt-out by default, service-level consent

  Key Benefits

✅ Backward compatible (null defaults to enabled)
✅ Granular control per analytics service
✅ First-launch admin modal (no YAML editing)
✅ Privacy-focused with opt-out defaults
✅ API-based config updates

---------

Co-authored-by: Connor Yoh <[email protected]>

frontend/src/components/layout/Workbench.tsx

@@ -6,6 +6,7 @@ import { useFileState } from '../../contexts/FileContext';
 import { useNavigationState, useNavigationActions } from '../../contexts/NavigationContext';
 import { isBaseWorkbench } from '../../types/workbench';
 import { useViewer } from '../../contexts/ViewerContext';
+import { useAppConfig } from '../../contexts/AppConfigContext';
 import './Workbench.css';
 
 import TopControls from '../shared/TopControls';
@@ -20,6 +21,7 @@ import DismissAllErrorsButton from '../shared/DismissAllErrorsButton';
 // No props needed - component uses contexts directly
 export default function Workbench() {
   const { isRainbowMode } = useRainbowThemeContext();
+  const { config } = useAppConfig();
 
   // Use context-based hooks to eliminate all prop drilling
   const { selectors } = useFileState();
@@ -188,7 +190,7 @@ export default function Workbench() {
         {renderMainContent()}
       </Box>
 
-      <Footer analyticsEnabled />
+      <Footer analyticsEnabled={config?.enableAnalytics === true} />
     </Box>
   );
 }