di: add a stub TierDetection; provide both actual impl and stub in AppModule

examples/llama.android/app/src/main/java/com/example/llama/di/AppModule.kt

@@ -3,6 +3,7 @@ package com.example.llama.di
 import android.content.Context
 import android.llama.cpp.InferenceEngine
 import android.llama.cpp.KleidiLlama
+import android.llama.cpp.TierDetection
 import android.llama.cpp.gguf.GgufMetadataReader
 import com.example.llama.data.local.AppDatabase
 import com.example.llama.data.remote.HuggingFaceApiService
@@ -18,6 +19,7 @@ import com.example.llama.engine.InferenceService
 import com.example.llama.engine.InferenceServiceImpl
 import com.example.llama.engine.ModelLoadingService
 import com.example.llama.engine.StubInferenceEngine
+import com.example.llama.engine.StubTierDetection
 import com.example.llama.monitoring.PerformanceMonitor
 import dagger.Binds
 import dagger.Module
@@ -71,6 +73,15 @@ internal abstract class AppModule {
             }
         }
 
+        @Provides
+        fun provideTierDetection(@ApplicationContext context: Context): TierDetection {
+            return if (USE_STUB_ENGINE) {
+                StubTierDetection
+            } else {
+                KleidiLlama.getTierDetection(context)
+            }
+        }
+
         @Provides
         fun providePerformanceMonitor(@ApplicationContext context: Context) = PerformanceMonitor(context)
 

examples/llama.android/app/src/main/java/com/example/llama/engine/StubTierDetection.kt

@@ -0,0 +1,19 @@
+package com.example.llama.engine
+
+import android.llama.cpp.LLamaTier
+import android.llama.cpp.TierDetection
+import android.util.Log
+
+/**
+ * A stub [TierDetection] for agile development & testing
+ */
+object StubTierDetection : TierDetection {
+    private val tag = StubTierDetection::class.java.simpleName
+
+    override val detectedTier: LLamaTier?
+        get() = LLamaTier.T2
+
+    override fun clearCache() {
+        Log.d(tag, "Cache cleared")
+    }
+}

examples/llama.android/app/src/main/java/com/example/llama/viewmodel/SettingsViewModel.kt

@@ -1,5 +1,7 @@
 package com.example.llama.viewmodel
 
+import android.llama.cpp.LLamaTier
+import android.llama.cpp.TierDetection
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.llama.data.preferences.UserPreferences
@@ -26,6 +28,7 @@ class SettingsViewModel @Inject constructor(
     private val userPreferences: UserPreferences,
     private val performanceMonitor: PerformanceMonitor,
     private val modelRepository: ModelRepository,
+    private val tierDetection: TierDetection,
 ) : ViewModel() {
 
     // Storage usage metrics
@@ -57,6 +60,9 @@ class SettingsViewModel @Inject constructor(
     private val _themeMode = MutableStateFlow(UserPreferences.THEME_MODE_AUTO)
     val themeMode: StateFlow<Int> = _themeMode.asStateFlow()
 
+    val detectedTier: LLamaTier?
+        get() = tierDetection.detectedTier
+
     init {
         viewModelScope.launch {
             // Load user preferences