feat(android): add native Android client

Kotlin + Jetpack Compose client for a self-hosted instance: manual
server setup and health check, auth with Keystore-backed tokens, album
and photo browsing with SSE live updates, upload queue in WorkManager
with HEIC-to-JPEG conversion, and Room/Coil offline cache. Add an
android Makefile target and revise project.md §17.

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">galo</string>
+</resources>

android/app/src/main/res/values/strings_upload.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="upload_channel_name">Загрузка в galo</string>
+    <string name="upload_channel_description">Прогресс фоновой загрузки фотографий и видео</string>
+</resources>

android/app/src/main/res/values/themes.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="Theme.Galo" parent="android:Theme.Material.Light.NoActionBar">
+        <item name="android:windowBackground">@android:color/white</item>
+    </style>
+</resources>