Complete i18n (zero hardcoded text) + 2FA/OAuth endpoints

- All placeholders, brand text, dates use t() function
- Dynamic date locale based on selected language
- 2FA/TOTP, WebAuthn, OAuth/:provider endpoints (placeholders)
- All 4 translation files updated (cs,he,ru,ua)

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

mobile/app.json

@@ -25,6 +25,10 @@
     },
     "web": {
       "favicon": "./assets/favicon.png"
-    }
+    },
+    "plugins": [
+      "expo-router",
+      "expo-secure-store"
+    ]
   }
 }

mobile/package.json

@@ -9,10 +9,21 @@
     "web": "expo start --web"
   },
   "dependencies": {
+    "@react-navigation/native": "^7.2.2",
     "expo": "~54.0.33",
+    "expo-constants": "~18.0.13",
+    "expo-device": "~8.0.10",
+    "expo-linking": "~8.0.11",
+    "expo-notifications": "~0.32.16",
+    "expo-router": "~6.0.23",
+    "expo-secure-store": "~15.0.8",
     "expo-status-bar": "~3.0.9",
     "react": "19.1.0",
-    "react-native": "0.81.5"
+    "react-native": "0.81.5",
+    "react-native-gesture-handler": "^2.30.1",
+    "react-native-reanimated": "^4.3.0",
+    "react-native-safe-area-context": "~5.6.0",
+    "react-native-screens": "~4.16.0"
   },
   "devDependencies": {
     "@types/react": "~19.1.0",