feat: add multi-provider support to chat widget

- Added support for multiple AI providers (Ollama, Gemini, OpenRouter, Copilot) with provider abstraction layer
- Created settings view with provider configuration and API key management
- Updated UI to show current provider status and handle provider-specific availability
- Modified reasoning mode to work exclusively with Ollama provider
- Added provider switching functionality with persistent settings
- Updated error messages and placeholders to be

reasoning_controller.py

@@ -15,6 +15,14 @@ class PreferencesState:
     reasoning_enabled: bool = False
     default_model: str | None = None
     theme: str = "default"
+    provider: str = "ollama"  # AI provider: "ollama", "gemini", "openrouter", "copilot"
+    api_keys: Dict[str, str] = None  # API keys for providers (gemini, openrouter)
+    copilot_oauth_token: str | None = None  # GitHub Copilot OAuth token
+    
+    def __post_init__(self):
+        """Initialize api_keys if None."""
+        if self.api_keys is None:
+            self.api_keys = {}
 
 
 class ReasoningController:
@@ -66,6 +74,10 @@ class ReasoningController:
         Returns:
             Dictionary of model-specific parameters
         """
+        # Only return options for Ollama (other providers don't use these)
+        if self._preferences.provider != "ollama":
+            return {}
+        
         if self._preferences.reasoning_enabled:
             # Thinking model settings
             return {
@@ -85,6 +97,33 @@ class ReasoningController:
                 "num_predict": 32768,
             }
     
+    def get_provider(self) -> str:
+        """Get the current AI provider."""
+        return self._preferences.provider
+    
+    def set_provider(self, provider: str) -> None:
+        """Set the AI provider."""
+        self._preferences.provider = provider
+        self._save_preferences()
+    
+    def get_api_key(self, provider: str) -> str | None:
+        """Get API key for a provider."""
+        return self._preferences.api_keys.get(provider)
+    
+    def set_api_key(self, provider: str, api_key: str) -> None:
+        """Set API key for a provider."""
+        self._preferences.api_keys[provider] = api_key
+        self._save_preferences()
+    
+    def get_copilot_token(self) -> str | None:
+        """Get GitHub Copilot OAuth token."""
+        return self._preferences.copilot_oauth_token
+    
+    def set_copilot_token(self, token: str | None) -> None:
+        """Set GitHub Copilot OAuth token."""
+        self._preferences.copilot_oauth_token = token
+        self._save_preferences()
+    
     def _load_preferences(self) -> PreferencesState:
         """Load preferences from disk or create defaults.
         
@@ -101,6 +140,9 @@ class ReasoningController:
                     reasoning_enabled=data.get("reasoning_enabled", False),
                     default_model=data.get("default_model"),
                     theme=data.get("theme", "default"),
+                    provider=data.get("provider", "ollama"),
+                    api_keys=data.get("api_keys", {}),
+                    copilot_oauth_token=data.get("copilot_oauth_token"),
                 )
         except (json.JSONDecodeError, OSError):
             # If file is corrupted or unreadable, return defaults