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

app/onboarding.tsx

@@ -116,6 +116,7 @@ function ProblemScreen({ onNext }: { onNext: () => void }) {
       <View style={styles.bottomAction}>
         <Pressable
           style={styles.ctaButton}
+          testID="onboarding-problem-cta"
           onPress={() => {
             haptics.buttonTap()
             onNext()
@@ -179,6 +180,7 @@ function EmpathyScreen({
           return (
             <Pressable
               key={item.id}
+              testID={`barrier-${item.id}`}
               style={[
                 styles.barrierCard,
                 selected && styles.barrierCardSelected,
@@ -206,6 +208,7 @@ function EmpathyScreen({
       <View style={styles.bottomAction}>
         <Pressable
           style={[styles.ctaButton, barriers.length === 0 && styles.ctaButtonDisabled]}
+          testID="onboarding-empathy-continue"
           onPress={() => {
             if (barriers.length > 0) {
               haptics.buttonTap()
@@ -350,6 +353,7 @@ function SolutionScreen({ onNext }: { onNext: () => void }) {
       <View style={styles.bottomAction}>
         <Pressable
           style={styles.ctaButton}
+          testID="onboarding-solution-cta"
           onPress={() => {
             haptics.buttonTap()
             onNext()
@@ -467,6 +471,7 @@ function WowScreen({ onNext }: { onNext: () => void }) {
       <Animated.View style={[styles.bottomAction, { opacity: ctaOpacity }]}>
         <Pressable
           style={styles.ctaButton}
+          testID="onboarding-wow-cta"
           onPress={() => {
             if (ctaReady) {
               haptics.buttonTap()
@@ -556,6 +561,7 @@ function PersonalizationScreen({
           placeholderTextColor={colors.text.hint}
           autoCapitalize="words"
           autoCorrect={false}
+          testID="name-input"
         />
       </View>
 
@@ -568,6 +574,7 @@ function PersonalizationScreen({
           {LEVELS.map((item) => (
             <Pressable
               key={item.value}
+              testID={`level-${item.value}`}
               style={[
                 styles.segmentButton,
                 level === item.value && styles.segmentButtonActive,
@@ -598,6 +605,7 @@ function PersonalizationScreen({
           {GOALS.map((item) => (
             <Pressable
               key={item.value}
+              testID={`goal-${item.value}`}
               style={[
                 styles.segmentButton,
                 goal === item.value && styles.segmentButtonActive,
@@ -628,6 +636,7 @@ function PersonalizationScreen({
           {FREQUENCIES.map((item) => (
             <Pressable
               key={item.value}
+              testID={`frequency-${item.value}x`}
               style={[
                 styles.segmentButton,
                 frequency === item.value && styles.segmentButtonActive,
@@ -658,6 +667,7 @@ function PersonalizationScreen({
       <View style={{ marginTop: SPACING[8] }}>
         <Pressable
           style={[styles.ctaButton, !name.trim() && styles.ctaButtonDisabled]}
+          testID="onboarding-personalization-continue"
           onPress={() => {
             if (name.trim()) {
               haptics.buttonTap()
@@ -828,6 +838,7 @@ function PaywallScreen({
       <View style={styles.pricingCards}>
         {/* Annual */}
         <Pressable
+          testID="plan-yearly"
           style={[
             styles.pricingCard,
             selectedPlan === 'premium-yearly' && styles.pricingCardSelected,
@@ -852,6 +863,7 @@ function PaywallScreen({
 
         {/* Monthly */}
         <Pressable
+          testID="plan-monthly"
           style={[
             styles.pricingCard,
             selectedPlan === 'premium-monthly' && styles.pricingCardSelected,
@@ -870,6 +882,7 @@ function PaywallScreen({
       {/* CTA */}
       <Pressable
         style={[styles.trialButton, isPurchasing && styles.ctaButtonDisabled]}
+        testID="subscribe-button"
         onPress={handlePurchase}
         disabled={isPurchasing}
       >
@@ -886,17 +899,21 @@ function PaywallScreen({
       </View>
 
       {/* Restore Purchases */}
-      <Pressable style={styles.restoreButton} onPress={handleRestore}>
+      <Pressable style={styles.restoreButton} onPress={handleRestore} testID="restore-purchases">
         <StyledText size={14} color={colors.text.hint}>
           {t('onboarding.paywall.restorePurchases')}
         </StyledText>
       </Pressable>
 
       {/* Skip */}
-      <Pressable style={styles.skipButton} onPress={() => {
-        track('onboarding_paywall_skipped')
-        onSkip()
-      }}>
+      <Pressable 
+        style={styles.skipButton} 
+        testID="skip-paywall"
+        onPress={() => {
+          track('onboarding_paywall_skipped')
+          onSkip()
+        }}
+      >
         <StyledText size={14} color={colors.text.hint}>
           {t('onboarding.paywall.skipButton')}
         </StyledText>
@@ -1241,6 +1258,7 @@ function createStyles(colors: ThemeColors) {
       flex: 1,
       paddingVertical: SPACING[5],
       alignItems: 'center',
+      justifyContent: 'center',
       borderRadius: RADIUS.GLASS_CARD,
       ...colors.glass.base,
     },