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/activity-tab.yaml

@@ -0,0 +1,82 @@
+# Activity Tab Flow Test
+# Tests the activity/stats dashboard screen
+# Prerequisite: User must have completed onboarding
+
+appId: com.millianlmx.tabatafit
+name: Activity Tab
+
+---
+# Start from home screen
+- assertVisible: "program-card-upper-body"
+
+# Navigate to Activity tab
+- tapOn:
+    text: "Activity"
+    optional: true
+- tapOn:
+    id: "activity-tab"
+    optional: true
+
+# Verify activity screen loaded — check for stats elements
+- assertVisible:
+    text: ".*Activity.*"
+    timeout: 5000
+
+# Check for streak display
+- assertVisible:
+    text: ".*streak.*"
+    timeout: 3000
+    optional: true
+
+# Check for workout count stats
+- assertVisible:
+    text: ".*workout.*"
+    timeout: 3000
+    optional: true
+
+# Check for calories display
+- assertVisible:
+    text: ".*cal.*"
+    timeout: 3000
+    optional: true
+
+# Scroll down to see weekly chart or history
+- scroll:
+    direction: DOWN
+    duration: 500
+
+# Check for weekly chart or activity history section
+- assertVisible:
+    text: ".*week.*"
+    timeout: 3000
+    optional: true
+
+# Scroll down further to see history
+- scroll:
+    direction: DOWN
+    duration: 500
+
+# Check for achievement badges if present
+- assertVisible:
+    text: ".*achievement.*"
+    timeout: 3000
+    optional: true
+
+# Scroll back to top
+- scroll:
+    direction: UP
+    duration: 1000
+
+# Navigate back to Home
+- tapOn:
+    text: "Home"
+    optional: true
+- tapOn:
+    id: "home-tab"
+    optional: true
+
+# Verify home screen
+- assertVisible:
+    id: "program-card-upper-body"
+    timeout: 5000
+    optional: true