Keep the Android connection alive in the background

The session moves from the connection screen's ViewModel into an
app-wide SessionController, and a foreground service keeps the process
running while connected:

- Its notification shows the server and status and offers Mute, Deafen
  and Disconnect.
- It declares microphone use only once the microphone is handed to the
  connection, as Android requires that permission to be granted then.
- It holds a low-latency Wi-Fi lock and a CPU wake lock, since voice
  goes out every 20 ms.
- When the system moves to another network, the session reconnects to
  where it was, as its socket stays bound to the old one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/app/build.gradle.kts

@@ -22,6 +22,7 @@ android {
     buildTypes {
         release {
             isMinifyEnabled = true
+            isShrinkResources = true
             proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
         }
     }
@@ -51,5 +52,5 @@ dependencies {
     implementation(libs.androidx.compose.material3)
     implementation(libs.androidx.activity.compose)
     implementation(libs.androidx.lifecycle.runtime.compose)
-    implementation(libs.androidx.lifecycle.viewmodel.compose)
+    implementation(libs.androidx.lifecycle.service)
 }