Add LAN car_select flow: real event handling, GameEvents JNI bridge, live car/upgrade/color capture, Compose UI example

Fixes the synthetic car_select jump for cold sessions, makes the loadout
exit chain safe for real (non-synthetic) events, and adds a native->Kotlin
GameEvents bridge (onMapLoaded/onRaceStarted/onRaceEnded/onUpgradesAccepted/
onCarSelected) so both the UI layer and a future native RatNet client can
learn what the player picked - car id, accepted upgrades, and paint color
(name + RGBA) are all resolved live from the game's own engine state
rather than a static extracted table, so they stay correct for any car
added later. Includes a Jetpack Compose overlay as a worked example of a
UI-side GameEventListener consumer.

Full investigation history, root causes, and the several dead ends ruled
out along the way are documented in PROGRESS.md (cont. 30-63b).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/build.gradle.kts

@@ -1,6 +1,7 @@
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.kotlin.compose)
 }
 
 android {
@@ -37,6 +38,9 @@ android {
     kotlinOptions {
         jvmTarget = "11"
     }
+    buildFeatures {
+        compose = true
+    }
 }
 
 dependencies {
@@ -48,6 +52,13 @@ dependencies {
     androidTestImplementation(libs.androidx.junit)
     androidTestImplementation(libs.androidx.espresso.core)
 
+    implementation(platform(libs.androidx.compose.bom))
+    implementation(libs.androidx.ui)
+    implementation(libs.androidx.ui.graphics)
+    implementation(libs.androidx.material3)
+    implementation(libs.androidx.activity.compose)
+    debugImplementation(libs.androidx.ui.tooling)
+
     implementation("com.parse.bolts:bolts-tasks:1.4.0")
     implementation("org.apache.httpcomponents:httpclient-android:4.3.5.1")
     implementation("com.google.code.gson:gson:2.7")