feat: add EAS build configuration for local APK builds

- Add eas.json with development, preview, and production profiles
- Configure preview profile for APK builds (arm64-v8a only)
- Add build:apk npm script for local builds
- Update app.json with app name and Android package
- Add expo-build-properties dependency
- Update CLAUDE.md with build documentation

apps/client/package.json

@@ -8,7 +8,8 @@
     "android": "expo start --android",
     "ios": "expo start --ios",
     "web": "expo start --web",
-    "lint": "expo lint"
+    "lint": "expo lint",
+    "build:apk": "eas build --platform android --profile preview --local"
   },
   "dependencies": {
     "@caldav/shared": "*",
@@ -18,6 +19,7 @@
     "@react-navigation/native": "^7.1.8",
     "@shopify/flash-list": "^2.0.2",
     "expo": "~54.0.25",
+    "expo-build-properties": "^1.0.10",
     "expo-constants": "~18.0.10",
     "expo-font": "~14.0.9",
     "expo-haptics": "~15.0.7",