add vault first time control

src/screens/MeScreen.tsx

@@ -14,9 +14,11 @@ import {
 import { LinearGradient } from 'expo-linear-gradient';
 import { Ionicons, Feather, MaterialCommunityIcons, FontAwesome5 } from '@expo/vector-icons';
 import { colors, typography, spacing, borderRadius, shadows } from '../theme/colors';
+import AsyncStorage from '@react-native-async-storage/async-storage';
 import { useAuth } from '../context/AuthContext';
 import { Heir, HeirStatus, PaymentStrategy } from '../types';
 import HeritageScreen from './HeritageScreen';
+import { VAULT_STORAGE_KEYS } from './SentinelScreen';
 
 // Mock heirs data
 const initialHeirs: Heir[] = [
@@ -308,6 +310,18 @@ export default function MeScreen() {
     );
   };
 
+  const handleResetVault = async () => {
+    try {
+      await AsyncStorage.multiRemove([
+        VAULT_STORAGE_KEYS.INITIALIZED,
+        VAULT_STORAGE_KEYS.SHARE_DEVICE,
+      ]);
+      Alert.alert('Done', 'Vault state reset. Go to Sentinel → Open Shadow Vault to see first-time flow.');
+    } catch (e) {
+      Alert.alert('Error', 'Failed to reset vault state.');
+    }
+  };
+
   return (
     <View style={styles.container}>
       <LinearGradient
@@ -885,6 +899,21 @@ export default function MeScreen() {
                   <Text style={styles.sanctumValue}>View</Text>
                 </View>
               </View>
+
+              {__DEV__ && (
+                <View style={styles.sanctumSection}>
+                  <Text style={styles.tideLabel}>DEV ONLY</Text>
+                  <TouchableOpacity
+                    style={styles.devResetButton}
+                    onPress={handleResetVault}
+                    activeOpacity={0.85}
+                  >
+                    <Ionicons name="refresh" size={16} color={colors.nautical.coral} />
+                    <Text style={styles.devResetText}>Reset Vault State</Text>
+                  </TouchableOpacity>
+                  <Text style={styles.sanctumHint}>Clear hasVaultInitialized & Share A. Test first-open flow.</Text>
+                </View>
+              )}
             </ScrollView>
             <View style={styles.tideModalButtons}>
               <TouchableOpacity
@@ -1814,6 +1843,23 @@ const styles = StyleSheet.create({
     fontSize: typography.fontSize.sm,
     color: colors.me.textSecondary,
   },
+  devResetButton: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    gap: spacing.sm,
+    paddingVertical: spacing.sm,
+    paddingHorizontal: spacing.md,
+    backgroundColor: `${colors.nautical.coral}15`,
+    borderRadius: borderRadius.lg,
+    borderWidth: 1,
+    borderColor: `${colors.nautical.coral}40`,
+    alignSelf: 'flex-start',
+  },
+  devResetText: {
+    fontSize: typography.fontSize.sm,
+    color: colors.nautical.coral,
+    fontWeight: '600',
+  },
   sanctumAlert: {
     flexDirection: 'row',
     alignItems: 'center',

src/screens/SentinelScreen.tsx

@@ -22,6 +22,7 @@ import AsyncStorage from '@react-native-async-storage/async-storage';
 import { colors, typography, spacing, borderRadius, shadows } from '../theme/colors';
 import { SystemStatus, KillSwitchLog } from '../types';
 import VaultScreen from './VaultScreen';
+import BiometricModal from '../components/common/BiometricModal';
 import {
   SSSShare,
   mnemonicToEntropy,
@@ -31,6 +32,12 @@ import {
   verifyShares,
 } from '../utils/sss';
 
+// Vault storage keys (for testing: clear these to simulate first-open)
+export const VAULT_STORAGE_KEYS = {
+  INITIALIZED: 'sentinel_vault_initialized',
+  SHARE_DEVICE: 'sentinel_share_device',
+} as const;
+
 // Nautical-themed mnemonic word list (unique words only)
 const MNEMONIC_WORDS = [
   'anchor', 'harbor', 'compass', 'lighthouse', 'current', 'ocean', 'tide', 'voyage',
@@ -166,9 +173,19 @@ export default function SentinelScreen() {
   const [sssShares, setSssShares] = useState<SSSShare[]>([]);
   const [showEmailForm, setShowEmailForm] = useState(false);
   const [emailAddress, setEmailAddress] = useState('');
+  const [emailRecipientType, setEmailRecipientType] = useState<'self' | 'heir'>('self');
   const [isCapturing, setIsCapturing] = useState(false);
+  const [hasVaultInitialized, setHasVaultInitialized] = useState<boolean | null>(null);
+  const [showSetupBiometric, setShowSetupBiometric] = useState(false);
   const mnemonicRef = useRef<View>(null);
 
+  // Load vault init status on mount (1.1)
+  useEffect(() => {
+    AsyncStorage.getItem(VAULT_STORAGE_KEYS.INITIALIZED)
+      .then((val) => setHasVaultInitialized(val === 'true'))
+      .catch(() => setHasVaultInitialized(false));
+  }, []);
+
   useEffect(() => {
     // Pulse animation
     const pulseAnimation = Animated.loop(
@@ -222,7 +239,7 @@ export default function SentinelScreen() {
     };
   }, [pulseAnim, glowAnim, rotateAnim]);
 
-  const openVaultWithMnemonic = () => {
+  const startFirstTimeSetup = () => {
     const words = generateMnemonic();
     const shares = generateSSSShares(words);
     setMnemonicWords(words);
@@ -231,12 +248,40 @@ export default function SentinelScreen() {
     setShowVault(false);
     setShowEmailForm(false);
     setEmailAddress('');
+    setEmailRecipientType('self');
 
-    // Store Share A (device share) locally
     if (shares[0]) {
-      AsyncStorage.setItem('sentinel_share_device', serializeShare(shares[0])).catch(() => {
+      AsyncStorage.setItem(VAULT_STORAGE_KEYS.SHARE_DEVICE, serializeShare(shares[0])).catch(() => {});
-        // Best-effort local store; UI remains available
+    }
-      });
+  };
+
+  const completeSetupAndEnterVault = () => {
+    setShowMnemonic(false);
+    setShowEmailForm(false);
+    setEmailAddress('');
+    setShowSetupBiometric(true);
+  };
+
+  const handleSetupBiometricSuccess = () => {
+    setShowSetupBiometric(false);
+    AsyncStorage.setItem(VAULT_STORAGE_KEYS.INITIALIZED, 'true').catch(() => {});
+    setHasVaultInitialized(true);
+    setShowVault(true);
+  };
+
+  const handleSetupBiometricSkip = () => {
+    setShowSetupBiometric(false);
+    AsyncStorage.setItem(VAULT_STORAGE_KEYS.INITIALIZED, 'true').catch(() => {});
+    setHasVaultInitialized(true);
+    setShowVault(true);
+  };
+
+  const handleOpenVault = () => {
+    if (hasVaultInitialized === true) {
+      setShowVault(true);
+      setShowMnemonic(false);
+    } else {
+      startFirstTimeSetup();
     }
   };
 
@@ -252,8 +297,7 @@ export default function SentinelScreen() {
         url: uri,
         message: 'Sentinel key backup',
       });
-      setShowMnemonic(false);
+      completeSetupAndEnterVault();
-      setShowVault(true);
     } catch (error) {
       Alert.alert('Screenshot failed', 'Please try again or use email backup.');
     } finally {
@@ -265,6 +309,10 @@ export default function SentinelScreen() {
     setShowEmailForm(true);
   };
 
+  const handleCompleteBackupLocal = () => {
+    completeSetupAndEnterVault();
+  };
+
   const handleSendEmail = async () => {
     const trimmed = emailAddress.trim();
     if (!trimmed || !/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(trimmed)) {
@@ -272,16 +320,21 @@ export default function SentinelScreen() {
       return;
     }
 
-    const subject = encodeURIComponent('Sentinel Vault Recovery Key');
+    const subject = encodeURIComponent(
-    const body = encodeURIComponent(`Your 12-word mnemonic:\n${mnemonicWords.join(' ')}`);
+      emailRecipientType === 'heir'
+        ? 'Sentinel Vault - Share C (Heir)'
+        : 'Sentinel Vault Recovery Key'
+    );
+    const body = encodeURIComponent(
+      emailRecipientType === 'heir'
+        ? `Share C (for heir, 2-of-3 required to recover):\n${sssShares[2] ? serializeShare(sssShares[2]) : ''}\n\nKeep this secure. Combined with Share B from Sentinel cloud, this can restore the vault.`
+        : `Your 12-word mnemonic (backup for yourself):\n${mnemonicWords.join(' ')}`
+    );
     const mailtoUrl = `mailto:${trimmed}?subject=${subject}&body=${body}`;
 
     try {
       await Linking.openURL(mailtoUrl);
-      setShowMnemonic(false);
+      completeSetupAndEnterVault();
-      setShowEmailForm(false);
-      setEmailAddress('');
-      setShowVault(true);
     } catch (error) {
       Alert.alert('Email failed', 'Unable to open email client.');
     }
@@ -450,7 +503,7 @@ export default function SentinelScreen() {
               </View>
               <TouchableOpacity
                 style={styles.vaultAccessButton}
-                onPress={openVaultWithMnemonic}
+                onPress={handleOpenVault}
                 activeOpacity={0.8}
                 accessibilityLabel="Open Shadow Vault"
                 accessibilityRole="button"
@@ -535,6 +588,12 @@ export default function SentinelScreen() {
         <KeyboardAvoidingView
           style={styles.mnemonicOverlay}
           behavior={Platform.OS === 'ios' ? 'padding' : undefined}
+        >
+          <ScrollView
+            style={styles.mnemonicScroll}
+            contentContainerStyle={styles.mnemonicScrollContent}
+            showsVerticalScrollIndicator={false}
+            keyboardShouldPersistTaps="handled"
           >
           <View ref={mnemonicRef} collapsable={false}>
             <LinearGradient
@@ -602,18 +661,36 @@ export default function SentinelScreen() {
               style={styles.mnemonicSecondaryButton}
               onPress={handleEmailBackup}
               activeOpacity={0.85}
-              accessibilityLabel="Send mnemonic backup via email"
+              accessibilityLabel="Send backup via email"
               accessibilityRole="button"
             >
               <Text style={styles.mnemonicSecondaryText}>EMAIL BACKUP</Text>
             </TouchableOpacity>
             {showEmailForm ? (
               <View style={styles.emailForm}>
+                <View style={styles.emailTypeRow}>
+                  <TouchableOpacity
+                    style={[styles.emailTypeButton, emailRecipientType === 'self' && styles.emailTypeButtonActive]}
+                    onPress={() => setEmailRecipientType('self')}
+                  >
+                    <Text style={[styles.emailTypeText, emailRecipientType === 'self' && styles.emailTypeTextActive]}>
+                      To Myself
+                    </Text>
+                  </TouchableOpacity>
+                  <TouchableOpacity
+                    style={[styles.emailTypeButton, emailRecipientType === 'heir' && styles.emailTypeButtonActive]}
+                    onPress={() => setEmailRecipientType('heir')}
+                  >
+                    <Text style={[styles.emailTypeText, emailRecipientType === 'heir' && styles.emailTypeTextActive]}>
+                      To Heir
+                    </Text>
+                  </TouchableOpacity>
+                </View>
                 <TextInput
                   style={styles.emailInput}
                   value={emailAddress}
                   onChangeText={setEmailAddress}
-                  placeholder="you@email.com"
+                  placeholder={emailRecipientType === 'heir' ? 'heir@email.com' : 'you@email.com'}
                   placeholderTextColor={colors.sentinel.textSecondary}
                   keyboardType="email-address"
                   autoCapitalize="none"
@@ -630,10 +707,30 @@ export default function SentinelScreen() {
                 </TouchableOpacity>
               </View>
             ) : null}
+            <TouchableOpacity
+              style={styles.mnemonicTertiaryButton}
+              onPress={handleCompleteBackupLocal}
+              activeOpacity={0.85}
+              accessibilityLabel="I've completed backup locally"
+              accessibilityRole="button"
+            >
+              <Text style={styles.mnemonicTertiaryText}>COMPLETE BACKUP (LOCAL)</Text>
+            </TouchableOpacity>
             </LinearGradient>
           </View>
+          </ScrollView>
         </KeyboardAvoidingView>
       </Modal>
+
+      {/* Biometric setup prompt after first-time backup (1.4) */}
+      <BiometricModal
+        visible={showSetupBiometric}
+        onSuccess={handleSetupBiometricSuccess}
+        onCancel={handleSetupBiometricSkip}
+        title="Quick Unlock"
+        message="Enable Face ID / Touch ID for faster access next time?"
+        isDark
+      />
     </View>
   );
 }
@@ -900,6 +997,13 @@ const styles = StyleSheet.create({
     justifyContent: 'center',
     padding: spacing.lg,
   },
+  mnemonicScroll: {
+    flex: 1,
+  },
+  mnemonicScrollContent: {
+    flexGrow: 1,
+    justifyContent: 'center',
+  },
   mnemonicCard: {
     borderRadius: borderRadius.xl,
     padding: spacing.lg,
@@ -1013,6 +1117,47 @@ const styles = StyleSheet.create({
     fontWeight: '700',
     letterSpacing: typography.letterSpacing.wide,
   },
+  mnemonicTertiaryButton: {
+    backgroundColor: 'transparent',
+    paddingVertical: spacing.sm,
+    borderRadius: borderRadius.full,
+    alignItems: 'center',
+    marginTop: spacing.sm,
+    borderWidth: 1,
+    borderColor: colors.sentinel.cardBorder,
+    borderStyle: 'dashed',
+  },
+  mnemonicTertiaryText: {
+    color: colors.sentinel.textSecondary,
+    fontWeight: '600',
+    letterSpacing: typography.letterSpacing.wide,
+    fontSize: typography.fontSize.sm,
+  },
+  emailTypeRow: {
+    flexDirection: 'row',
+    gap: spacing.sm,
+    marginBottom: spacing.sm,
+  },
+  emailTypeButton: {
+    flex: 1,
+    paddingVertical: spacing.sm,
+    borderRadius: borderRadius.lg,
+    alignItems: 'center',
+    borderWidth: 1,
+    borderColor: colors.sentinel.cardBorder,
+  },
+  emailTypeButtonActive: {
+    borderColor: colors.sentinel.primary,
+    backgroundColor: `${colors.sentinel.primary}15`,
+  },
+  emailTypeText: {
+    fontSize: typography.fontSize.sm,
+    color: colors.sentinel.textSecondary,
+    fontWeight: '600',
+  },
+  emailTypeTextActive: {
+    color: colors.sentinel.primary,
+  },
   emailForm: {
     marginTop: spacing.sm,
   },

src/utils/sss.ts

@@ -5,7 +5,12 @@
  * - Secret is split into 3 shares
  * - Any 2 shares can recover the original secret
  *
- * Based on the Sentinel crypto_core_demo Python implementation.
+ * Correspondence with crypto_core_demo (Python):
+ * - sp_trust_sharding.py: split_to_shares(), recover_from_shares()
+ * - Same algorithm: f(x) = secret + a*x (mod P), Lagrange interpolation
+ * - Difference: entropy conversion. Python uses BIP-39 (mnemonic.to_entropy);
+ *   we use custom word list index-based encoding for compatibility with
+ *   existing MNEMONIC_WORDS. SSS split/recover logic is identical.
  */
 
 // Use a large prime for the finite field