feat(mobile): Android prep — icons/splash assets, permissions, FCM setup

- resources/: 1024 icon.png + 2732 splash.png/splash-dark.png generated from the
  PWA icon + brand blue; wired @capacitor/assets (npm run assets) + splash-screen plugin.
- ANDROID_SETUP.md: end-to-end guide (SDK setup, cap add android, manifest permissions,
  Firebase/google-services.json + Gradle, run, Play AAB build) for package com.bizgaze.connect.
- android-permissions.xml: paste-ready POST_NOTIFICATIONS + camera/mic/WebRTC perms.
- mobile/README links the guide; setup adds `npm run assets`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

mobile/resources/README.md

@@ -0,0 +1,21 @@
+# App icon & splash source images
+
+`@capacitor/assets` generates every Android (and iOS) icon/splash density from these masters.
+
+| File | Size | Purpose |
+|------|------|---------|
+| `icon.png` | 1024×1024 | App icon (all densities + Android adaptive icon) |
+| `splash.png` | 2732×2732 | Launch splash (light) |
+| `splash-dark.png` | 2732×2732 | Launch splash (dark mode) |
+
+These were generated from the existing PWA icon (`server/public/icon-512.png`) + brand blue
+`#1F3B73`. To rebrand, replace these three files (keep the sizes) and re-run:
+
+```bash
+cd mobile
+npm run assets        # Android only  (npm run assets:all for iOS too)
+npx cap sync
+```
+
+Tip: for the sharpest result, drop a true 1024×1024 `icon.png` (and a 2732×2732 `splash.png`)
+exported from the design source rather than an upscale.