Initialize Expo mobile app with tab navigation and monorepo support

- Expo managed project at apps/mobile/ with TypeScript
- Expo Router with 4 tabs: Map, Routes, Activities, Profile
- app.config.ts with monorepo experiment, bundle IDs, scheme
- Workspace packages linked: api, gpx, i18n, map-core, types
- Profile tab imports API_VERSION from @trails-cool/api to verify
  shared package resolution

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

apps/mobile/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "@trails-cool/mobile",
+  "version": "0.0.1",
+  "private": true,
+  "main": "index.ts",
+  "scripts": {
+    "start": "expo start",
+    "android": "expo start --android",
+    "ios": "expo start --ios",
+    "web": "expo start --web"
+  },
+  "dependencies": {
+    "@trails-cool/api": "workspace:*",
+    "@trails-cool/gpx": "workspace:*",
+    "@trails-cool/i18n": "workspace:*",
+    "@trails-cool/map-core": "workspace:*",
+    "@trails-cool/types": "workspace:*",
+    "expo": "~54.0.33",
+    "expo-router": "~4.0.22",
+    "expo-status-bar": "~3.0.9",
+    "react": "19.1.0",
+    "react-native": "0.81.5",
+    "react-native-safe-area-context": "~5.4.0",
+    "react-native-screens": "~4.11.0"
+  },
+  "devDependencies": {
+    "@types/react": "~19.1.0",
+    "typescript": "~5.9.2"
+  }
+}