feat: initial project scaffold

- Android Auto CarAppService, Session, Screen
- Voice pipeline: STT (SpeechManager), TTS (TTSManager), VoiceStateMachine
- Matrix REST client (login, send, sync) - no E2EE, raw API
- FCM push receiver with response dedup
- Network monitor + offline message queue
- Phone setup activity stub
- Full architecture spec in docs/ARCHITECTURE.md

app/src/main/java/farm/hobbs/clippyauto/ClippyAutoApp.kt

@@ -0,0 +1,22 @@
+package farm.hobbs.clippyauto
+
+import android.app.Application
+
+class ClippyAutoApp : Application() {
+
+    lateinit var matrixClient: farm.hobbs.clippyauto.matrix.MatrixRestClient
+        private set
+
+    override fun onCreate() {
+        super.onCreate()
+        instance = this
+        matrixClient = farm.hobbs.clippyauto.matrix.MatrixRestClient(
+            homeserverUrl = "https://mess.hobbs.farm"
+        )
+    }
+
+    companion object {
+        lateinit var instance: ClippyAutoApp
+            private set
+    }
+}