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

settings.gradle.kts

@@ -0,0 +1,17 @@
+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolution {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "ClippyAuto"
+include(":app")