Implement MCP OAuth authentication system

- Add MCPOAuthProvider implementing OAuthClientProvider interface
- Implement popup-based OAuth flow with message passing
- Add automatic connection retry after OAuth completion
- Support client registration persistence per server URL
- Add proper error suppression for expected OAuth UnauthorizedErrors
- Create comprehensive OAuth implementation documentation
- Clean up debug logging with emoji status indicators

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/types/mcp.ts

@@ -0,0 +1,132 @@
+// MCP provider types and interfaces
+
+import type { Client } from '@modelcontextprotocol/sdk/client/index.js';
+import type { Tool } from './inference';
+
+export interface MCPServerConfig {
+  name: string;                 // User-provided display name
+  url: string;                  // Server endpoint URL
+  transport?: 'sse' | 'streamable-http' | 'auto'; // Default: auto-detect
+  authType?: 'none' | 'oauth'; // Default: none
+  oauthConfig?: {
+    clientId?: string;
+    authUrl?: string;           // OAuth authorization endpoint
+    tokenUrl?: string;          // Token exchange endpoint
+    scope?: string;             // OAuth scope
+    redirectUri?: string;       // Override default redirect URI
+  };
+  autoReconnect?: boolean;      // Default: true
+  maxReconnectAttempts?: number; // Default: 5
+}
+
+export interface MCPMessage {
+  timestamp: Date;
+  direction: 'sent' | 'received';
+  type: 'request' | 'response' | 'notification';
+  method?: string;
+  id?: string | number;
+  content: any;
+  error?: any;
+}
+
+export interface MCPResource {
+  uri: string;
+  name: string;
+  description?: string;
+  mimeType?: string;
+}
+
+export interface MCPPrompt {
+  name: string;
+  description?: string;
+  arguments?: Array<{
+    name: string;
+    description?: string;
+    required?: boolean;
+  }>;
+}
+
+export interface MCPConnection {
+  id: string;                    // Unique connection identifier
+  name: string;                  // User-provided server name
+  url: string;                   // Server URL
+  status: 'connecting' | 'connected' | 'failed' | 'disconnected';
+  client?: Client;               // MCP SDK client instance
+  transport: 'sse' | 'streamable-http';
+  authType: 'none' | 'oauth';
+  
+  // Available capabilities
+  tools: Tool[];                 // Tools with name-prefixed identifiers
+  resources: MCPResource[];      // Available resources
+  prompts: MCPPrompt[];         // Available prompts
+  
+  // Connection metadata
+  error?: string;               // Last error message
+  lastConnected?: Date;         // Last successful connection
+  connectionAttempts: number;   // Number of reconnection attempts
+  
+  // Configuration
+  config: MCPServerConfig;
+}
+
+export interface MCPConnectionManager {
+  // Connection lifecycle
+  connect(): Promise<void>;
+  disconnect(): void;
+  reconnect(): Promise<void>;
+  
+  // Capability discovery
+  discoverTools(): Promise<Tool[]>;
+  discoverResources(): Promise<MCPResource[]>;
+  discoverPrompts(): Promise<MCPPrompt[]>;
+  
+  // Tool execution
+  callTool(toolName: string, args: any): Promise<any>;
+  
+  // Status
+  getStatus(): MCPConnection['status'];
+  getConnection(): MCPConnection;
+  
+  // Connection state updates
+  setConnectionUpdateCallback(callback: () => void): void;
+}
+
+export interface MCPError {
+  type: 'connection' | 'auth' | 'tool_execution' | 'protocol' | 'transport';
+  message: string;
+  details?: any;
+  connectionId?: string;
+  retryable: boolean;
+}
+
+export interface MCPContextValue {
+  // Connection state
+  connections: MCPConnection[];
+  isLoading: boolean;
+  error: string | null;
+  
+  // Connection management
+  addMcpServer: (config: MCPServerConfig) => Promise<string>; // Returns connection ID
+  removeMcpServer: (connectionId: string) => void;
+  reconnectServer: (connectionId: string) => Promise<void>;
+  
+  // Tool access (explicit server routing)
+  getAllTools: () => Tool[];                    // All tools with prefixed names
+  getToolsForServer: (connectionId: string) => Tool[];
+  callTool: (connectionId: string, toolName: string, args: any) => Promise<any>;
+  
+  // Resource access
+  getAllResources: () => MCPResource[];
+  getResourcesForServer: (connectionId: string) => MCPResource[];
+  
+  // Status and debugging
+  getConnectedServers: () => MCPConnection[];
+  getServerStatus: (connectionId: string) => MCPConnection['status'];
+  getConnectionById: (connectionId: string) => MCPConnection | undefined;
+  
+  // Connection configuration
+  updateServerConfig: (connectionId: string, config: Partial<MCPServerConfig>) => void;
+  
+  // OAuth handling
+  handleOAuthCallback: (connectionId: string, authorizationCode: string) => Promise<void>;
+}