feat: EAS build config for Android APK + BUILD.md (FIBEROPS-210)

- Add versionCode: 1 to app.json android section
- Add preview-local build profile to eas.json (local Gradle build)
- Add build:android:apk and build:android:local npm scripts
- Add BUILD.md documenting EAS cloud and local build instructions

BUILD.md

@@ -0,0 +1,59 @@
+# Building FiberOps Android APK
+
+## Requirements
+
+- [Expo account](https://expo.dev) — register at expo.dev
+- EAS CLI: `npm install -g eas-cli`
+- Authenticate: `eas login`
+
+## Build (EAS Cloud — recommended)
+
+Builds the APK on Expo's cloud infrastructure. No local Android SDK needed.
+
+```bash
+eas build --profile preview --platform android
+```
+
+Or via npm script:
+
+```bash
+npm run build:android:apk
+```
+
+The build will be queued on EAS. Once complete, download the `.apk` from the Expo dashboard or the URL printed in the CLI output.
+
+## Build (local — requires Android SDK)
+
+Requires Android SDK installed and `ANDROID_HOME` set.
+
+```bash
+npm run build:android:local
+# or directly:
+eas build --local --profile preview --platform android
+```
+
+Alternatively, use the Expo CLI directly:
+
+```bash
+npx expo run:android --variant release
+```
+
+## Distribution
+
+The `preview` profile is configured for **internal distribution** (`buildType: apk`). Share the `.apk` file directly with testers — no Play Store submission needed.
+
+## Current status
+
+- QA passed: MOB.1 (manual tasks), MOB.2 (remittance review)
+- EAS project ID: `15d21320-57f5-4fb6-a116-82d222d914e2`
+- Package: `com.fiberops.mobile`
+- Version: `1.0.0` (versionCode: 1)
+
+## EAS build profiles
+
+| Profile | Distribution | Output | Use case |
+|---------|-------------|--------|----------|
+| `preview` | internal | APK (EAS cloud) | QA / internal testing |
+| `preview-local` | internal | APK (local Gradle) | Offline / CI builds |
+| `development` | internal | Dev client | Development |
+| `production` | store | AAB | Play Store release |