feat(KB-057): add interactive terminal to dashboard

- Add backend terminal API with session management and SSE streaming
- Create useTerminal hook for command execution and history navigation
- Implement interactive TerminalModal with real-time output display
- Add terminal button to Header for quick access
- Style terminal with CSS variables and responsive design
- Add keyboard shortcuts (Ctrl+C to kill, Ctrl+L to clear, arrow keys for history)
- Add security validation for shell commands

packages/dashboard/app/components/__tests__/TerminalModal.test.tsx

@@ -1,5 +1,5 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
-import { render, screen, waitFor, act, fireEvent } from "@testing-library/react";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
 import { TerminalModal } from "../TerminalModal";
 import * as useTerminalModule from "../../hooks/useTerminal";
 
@@ -65,7 +65,6 @@ describe("TerminalModal", () => {
     const { container } = render(
       <TerminalModal isOpen={false} onClose={mockOnClose} />
     );
-
     expect(container.firstChild).toBeNull();
   });