feat: Brainstorm Topics with GSC + Issue #518 fixes + Blog Editor enhancements

Issue #518 - Subscription not updating after checkout:
- Fix stale closure in SubscriptionContext checkout polling (use subscriptionRef)
- Move checkout success polling from InitialRouteHandler into SubscriptionContext
- Remove redundant polling code from InitialRouteHandler
- Fix plan label: 'Free' instead of 'No Plan', proper capitalization
- Add plan refresh button in UserBadge
- Add 'View Costing Details' to UserBadge dropdown
- Rename 'ALwrity Podcast Maker' to 'Podcast Creator' across UI
- Clean subscription=success URL param after verification

Blog Writer WYSIWYG Editor enhancements:
- Per-section preview toggle (view/edit icons)
- Enhanced hover-based toolbar
- Circular SVG progress stats bar with detailed tooltip
- Research tool chips in stats bar footer
- Per-section TTS with useTextToSpeech hook (browser native)
- Full blog preview modal with print/PDF support
- PlayAllTTSButton: sequential playback with progress bar
- OnThisPageNav: floating sidebar with scroll tracking
- Section data attributes for scroll anchoring

GSC Brainstorm Topics feature:
- Backend: gsc_brainstorm_service.py (rule-based + LLM recommendations)
- Backend: POST /gsc/brainstorm endpoint with 3-word minimum validation
- Frontend: gscBrainstorm.ts API client
- Frontend: useGSCBrainstormConnection hook (popup OAuth, no /onboarding redirect)
- Frontend: useGSCBrainstorm hook (connect check + brainstorm call)
- Frontend: GSCBrainstormModal (3-tab results: Opportunities, Gaps, AI Recs)
- Frontend: BrainstormButton (visible at 3+ words, GSC connect overlay)
- Wire BrainstormButton into ManualResearchForm and ResearchAction
- Add blog_writer to gsc_auth router features for ALWRITY_ENABLED_FEATURES

frontend/src/components/OnboardingWizard/common/usePlatformConnections.ts

@@ -42,9 +42,6 @@ export const usePlatformConnections = () => {
       });
       setToastMessage('Wix account connected successfully!');
       setShowToast(true);
-      // Clean URL
-      const clean = window.location.pathname + window.location.hash;
-      window.history.replaceState({}, document.title, clean || '/');
     }
   }, [setConnectedPlatforms, setToastMessage]);
 
@@ -79,7 +76,13 @@ export const usePlatformConnections = () => {
       // 2) Key by state so callback can look up by state value
       try { sessionStorage.setItem(`wix_oauth_data_${oauthData.state}`, JSON.stringify(oauthData)); } catch {}
       // 3) window.name persists across top-level redirects even when origin changes
-      try { (window as any).name = `WIX_OAUTH::${btoa(JSON.stringify(oauthData))}`; } catch {}
+      try {
+        const redirectTo = sessionStorage.getItem('wix_oauth_redirect') || window.location.href;
+        console.log('[handleWixConnect] Storing redirect_to in window.name:', redirectTo);
+        (window as any).name = `WIX_OAUTH::${btoa(JSON.stringify({ ...oauthData, redirect_to: redirectTo }))}`;
+      } catch (e) {
+        console.error('[handleWixConnect] Failed to set window.name:', e);
+      }
       const { authUrl } = await wixClient.auth.getAuthUrl(oauthData);
       window.location.href = authUrl;
     } catch (error) {