fix(android): resolve build errors in terminal scaffold

- Fix settings.gradle.kts: dependencyResolution → dependencyResolutionManagement
- Fix Hilt version: 2.54.1 (non-existent) → 2.51.1
- Fix LoyaltyApi.kt: remove decorative unicode comments causing
  "unclosed comment" errors, fix /api/v1/store/loyalty/* pattern
  in KDoc that Kotlin parsed as block comment start
- Add placeholder launcher icons (purple square, all densities)

App now builds and runs on Pixel Tablet emulator: Setup → PIN → Terminal.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

clients/terminal-android/settings.gradle.kts

@@ -6,8 +6,9 @@ pluginManagement {
     }
 }
 
-dependencyResolution {
-    @Suppress("UnstableApiUsage")
+@Suppress("UnstableApiUsage")
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
     repositories {
         google()
         mavenCentral()