chore(gradle): fix code-review findings on app module setup

- Restore 4-space indent on kotlin-compose plugin alias (regression from
  the previous cleanup commit)
- Fix invalid ProGuard rule: HiltAndroidApp is an annotation type, not
  a class - use '-keep @dagger.hilt.android.HiltAndroidApp class *' to
  actually retain the @HiltAndroidApp-annotated Application
- Remove vectorDrawables.useSupportLibrary - dead config since minSdk 29
  (native VectorDrawable support since API 21)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

build.gradle.kts

@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
     alias(libs.plugins.android.application) apply false
-alias(libs.plugins.kotlin.compose) apply false
+    alias(libs.plugins.kotlin.compose) apply false
     alias(libs.plugins.ksp) apply false
     alias(libs.plugins.hilt) apply false
 }