Fix MCP form input and add reactive MCP server state

- Fix space key not working in MCP add form by handling evt.name === "space"
  - Add support for multi-character paste sequences via evt.sequence
  - Add MCPServerDisplay type to types/tui.ts for UI display
  - Add mcpServers reactive state to app store with setMcpServers,
    addMcpServer, and updateMcpServerStatus actions
  - Update session.tsx to use store's mcpServers instead of static props
  - Update execute.tsx to update store when server is added/connected
  - Remove duplicate MCPServer interfaces from app.tsx, session.tsx,
    and mcp-select.tsx in favor of shared MCPServerDisplay type

src/types/tui.ts

@@ -246,6 +246,19 @@ export interface StreamingLogState {
   isStreaming: boolean;
 }
 
+// ============================================================================
+// MCP Types (for UI display)
+// ============================================================================
+
+export type MCPServerStatus = "connected" | "disconnected" | "error";
+
+export interface MCPServerDisplay {
+  id: string;
+  name: string;
+  status: MCPServerStatus;
+  description?: string;
+}
+
 // ============================================================================
 // Component Props Types
 // ============================================================================