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

CLAUDE.md

@@ -23,6 +23,7 @@ npm run android -w @caldav/client      # Start on Android
 npm run ios -w @caldav/client          # Start on iOS
 npm run web -w @caldav/client          # Start web version
 npm run lint -w @caldav/client         # Run ESLint
+npm run build:apk -w @caldav/client    # Build APK locally with EAS
 ```
 
 ### Server (apps/server) - Express.js backend
@@ -42,6 +43,7 @@ npm run start -w @caldav/server        # Run compiled server (port 3000)
 | | NativeWind | Tailwind CSS for React Native |
 | | Zustand | State management |
 | | FlashList | High-performance lists |
+| | EAS Build | Local APK/IPA builds |
 | Backend | Express.js | Web framework |
 | | MongoDB | Database |
 | | Mongoose | ODM |
@@ -404,6 +406,29 @@ NODE_ENV=development        # development = pretty logs, production = JSON
 - `ChatStore`: Zustand store with addMessage(), addMessages(), updateMessage(), clearMessages() - loads from server on mount and persists across tab switches
 - Event Detail and Note screens exist as skeletons
 
+## Building
+
+### Local APK Build with EAS
+```bash
+npm run build:apk -w @caldav/client
+```
+
+This uses the `preview` profile from `eas.json` which builds an APK with:
+- `arm64-v8a` architecture only (smaller APK size)
+- No credentials required (`withoutCredentials: true`)
+- Internal distribution
+
+**Requirements:** Android SDK and Java must be installed locally.
+
+**EAS Configuration:** `apps/client/eas.json` contains build profiles:
+- `development`: Development client with internal distribution
+- `preview`: APK build for testing (used by `build:apk`)
+- `production`: Production build with auto-increment versioning
+
+**App Identity:**
+- Package name: `com.gilmour109.calchat`
+- EAS Project ID: `b722dde6-7d89-48ff-9095-e007e7c7da87`
+
 ## Documentation
 
 Detailed architecture diagrams are in `docs/`:

apps/client/app.json

@@ -1,11 +1,10 @@
 {
   "expo": {
     "jsEngine": "hermes",
-    "name": "caldav",
+    "name": "CalChat",
     "slug": "caldav",
     "version": "1.0.0",
     "orientation": "portrait",
-    "icon": "./assets/images/icon.png",
     "scheme": "caldav",
     "userInterfaceStyle": "automatic",
     "newArchEnabled": true,
@@ -13,38 +12,26 @@
       "supportsTablet": true
     },
     "android": {
-      "adaptiveIcon": {
+      "package": "com.gilmour109.calchat",
-        "backgroundColor": "#E6F4FE",
-        "foregroundImage": "./assets/images/android-icon-foreground.png",
-        "backgroundImage": "./assets/images/android-icon-background.png",
-        "monochromeImage": "./assets/images/android-icon-monochrome.png"
-      },
       "edgeToEdgeEnabled": true,
       "predictiveBackGestureEnabled": false
     },
     "web": {
       "output": "static",
-      "favicon": "./assets/images/favicon.png",
       "bundler": "metro"
     },
     "plugins": [
-      "expo-router",
+      "expo-router"
-      [
-        "expo-splash-screen",
-        {
-          "image": "./assets/images/splash-icon.png",
-          "imageWidth": 200,
-          "resizeMode": "contain",
-          "backgroundColor": "#ffffff",
-          "dark": {
-            "backgroundColor": "#000000"
-          }
-        }
-      ]
     ],
     "experiments": {
       "typedRoutes": true,
       "reactCompiler": true
+    },
+    "extra": {
+      "router": {},
+      "eas": {
+        "projectId": "b722dde6-7d89-48ff-9095-e007e7c7da87"
+      }
     }
   }
 }

apps/client/eas.json

@@ -0,0 +1,28 @@
+{
+  "cli": {
+    "version": ">= 16.28.0",
+    "appVersionSource": "remote"
+  },
+  "build": {
+    "development": {
+      "developmentClient": true,
+      "distribution": "internal"
+    },
+    "preview": {
+      "distribution": "internal",
+      "android": {
+        "buildType": "apk",
+        "withoutCredentials": true
+      },
+      "env": {
+        "ORG_GRADLE_PROJECT_reactNativeArchitectures": "arm64-v8a"
+      }
+    },
+    "production": {
+      "autoIncrement": true
+    }
+  },
+  "submit": {
+    "production": {}
+  }
+}

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",

package-lock.json

@@ -28,6 +28,7 @@
         "@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",
@@ -7303,6 +7304,53 @@
         "react-native": "*"
       }
     },
+    "node_modules/expo-build-properties": {
+      "version": "1.0.10",
+      "resolved": "https://registry.npmjs.org/expo-build-properties/-/expo-build-properties-1.0.10.tgz",
+      "integrity": "sha512-mFCZbrbrv0AP5RB151tAoRzwRJelqM7bCJzCkxpu+owOyH+p/rFC/q7H5q8B9EpVWj8etaIuszR+gKwohpmu1Q==",
+      "license": "MIT",
+      "dependencies": {
+        "ajv": "^8.11.0",
+        "semver": "^7.6.0"
+      },
+      "peerDependencies": {
+        "expo": "*"
+      }
+    },
+    "node_modules/expo-build-properties/node_modules/ajv": {
+      "version": "8.17.1",
+      "resolved": "https://registry.npmjs.org/ajv/-/ajv-8.17.1.tgz",
+      "integrity": "sha512-B/gBuNg5SiMTrPkC+A2+cW0RszwxYmn6VYxB/inlBStS5nx6xHIt/ehKRhIMhqusl7a8LjQoZnjCs5vhwxOQ1g==",
+      "license": "MIT",
+      "dependencies": {
+        "fast-deep-equal": "^3.1.3",
+        "fast-uri": "^3.0.1",
+        "json-schema-traverse": "^1.0.0",
+        "require-from-string": "^2.0.2"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/epoberezkin"
+      }
+    },
+    "node_modules/expo-build-properties/node_modules/json-schema-traverse": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-1.0.0.tgz",
+      "integrity": "sha512-NM8/P9n3XjXhIZn1lLhkFaACTOURQXjWhV4BA/RnOv8xvgqtqpAX9IO4mRQxSx1Rlo4tqzeqb0sOlruaOy3dug==",
+      "license": "MIT"
+    },
+    "node_modules/expo-build-properties/node_modules/semver": {
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
+      "license": "ISC",
+      "bin": {
+        "semver": "bin/semver.js"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/expo-constants": {
       "version": "18.0.11",
       "resolved": "https://registry.npmjs.org/expo-constants/-/expo-constants-18.0.11.tgz",
@@ -8013,6 +8061,22 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/fast-uri": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/fast-uri/-/fast-uri-3.1.0.tgz",
+      "integrity": "sha512-iPeeDKJSWf4IEOasVVrknXpaBV0IApz/gp7S2bb7Z4Lljbl2MGJRqInZiUrQwV16cpzw/D3S5j5Julj/gT52AA==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/fastify"
+        },
+        {
+          "type": "opencollective",
+          "url": "https://opencollective.com/fastify"
+        }
+      ],
+      "license": "BSD-3-Clause"
+    },
     "node_modules/fastq": {
       "version": "1.19.1",
       "resolved": "https://registry.npmjs.org/fastq/-/fastq-1.19.1.tgz",