feat(analytics): add Web Vitals tracking, GlitchTip user context, and funnel events

- Add web-vitals package with LCP/CLS/INP/FCP/TTFB → Umami tracking
- Set GlitchTip user context on login, clear on logout
- Add funnel events: first_content_created, user_return_visit,
  second_module_used, guest_converted
- Track first content via Dexie creating hook (fires once per user)
- Track module usage via route navigation effect
- Track guest→registered conversion on signup

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-utils/src/analytics.ts

@@ -328,6 +328,16 @@ export const ManaCoreEvents = {
 		track.manacore('widget_resized', { widget_type: widgetType, size }),
 	creditsTabViewed: (tab: string) => track.manacore('credits_tab_viewed', { tab }),
 	profileUpdated: () => track.manacore('profile_updated'),
+
+	// Funnel events — track key activation & retention moments
+	/** User created their first piece of content in any module */
+	firstContentCreated: (appId: string) => track.manacore('first_content_created', { app: appId }),
+	/** User returned after first session (fired once per user) */
+	userReturnVisit: () => track.manacore('user_return_visit'),
+	/** User used a second module (cross-app engagement) */
+	secondModuleUsed: (appId: string) => track.manacore('second_module_used', { app: appId }),
+	/** Guest user converted to registered user */
+	guestConverted: () => track.manacore('guest_converted'),
 };
 
 /**