Update LiteRT-LM implementation with accurate iOS status

- Document that Swift APIs are 'coming soon' per Google
- Add C++ bridge integration guide
- Create stub implementation that explains current limitations
- Add LITERT_IOS_STATUS.md with detailed integration options
- Fix MainViewModel to match MainView property expectations

SleepyAgent/UI/ViewModels/MainViewModel.swift

@@ -16,6 +16,12 @@ class MainViewModel: ObservableObject {
     @Published var conversations: [ConversationInfo] = []
     @Published var currentConversationId: UUID = UUID()
     
+    // Computed properties for view state
+    var isLoading: Bool { isGenerating && currentResponse.isEmpty }
+    var isProcessing: Bool { isGenerating }
+    var isExecutingTool: Bool { false } // TODO: Implement tool execution state
+    var streamingText: String { currentResponse }
+    
     private let agent: Agent
     private let audioRecorder: AudioRecorder
     private let ttsService: TtsService
@@ -41,6 +47,11 @@ class MainViewModel: ObservableObject {
         await processTextMessage(text)
     }
     
+    func sendMessage(text: String) async {
+        guard !text.isEmpty else { return }
+        await processTextMessage(text)
+    }
+    
     func sendImage(_ image: UIImage, text: String = "") async {
         selectedImage = image
         let displayText = text.isEmpty ? "[Image]" : text
@@ -156,6 +167,11 @@ class MainViewModel: ObservableObject {
         errorMessage = message
         showError = true
     }
+    
+    func dismissError() {
+        showError = false
+        errorMessage = nil
+    }
 }
 
 struct ConversationInfo: Identifiable {