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"
+    ]
   }
 }