feat: explore tab, React Query data layer, programs, sync, analytics, testing infrastructure

- Replace browse tab with Supabase-connected explore tab with filters
- Add React Query for data fetching with loading states
- Add 3 structured programs with weekly progression
- Add Supabase anonymous auth sync service
- Add PostHog analytics with screen tracking and events
- Add comprehensive test strategy (Vitest + Maestro E2E)
- Add RevenueCat subscription system with DEV simulation
- Add i18n translations for new screens (EN/FR/DE/ES)
- Add data deletion modal, sync consent modal
- Add assessment screen and program routes
- Add GitHub Actions CI workflow
- Update activity store with sync integration

.maestro/flows/tab-navigation.yaml

@@ -0,0 +1,45 @@
+# Tab Navigation Test
+# Tests switching between all tabs in the app
+# Prerequisite: User must have completed onboarding
+
+appId: com.millianlmx.tabatafit
+name: Tab Navigation
+
+---
+# Start on home tab
+- assertVisible: "program-card-upper-body"
+
+# Navigate to Explore tab
+- tapOn:
+    text: "Explore"
+    optional: true
+- tapOn:
+    id: "explore-tab"
+    optional: true
+
+# Navigate to Activity tab
+- tapOn:
+    text: "Activity"
+    optional: true
+- tapOn:
+    id: "activity-tab"
+    optional: true
+
+# Navigate to Profile tab
+- tapOn:
+    text: "Profile"
+    optional: true
+- tapOn:
+    id: "profile-tab"
+    optional: true
+
+# Navigate back to Home
+- tapOn:
+    text: "Home"
+    optional: true
+- tapOn:
+    id: "home-tab"
+    optional: true
+
+# Verify home screen
+- assertVisible: "program-card-upper-body"