Add Playwright E2E tests for Command Palette and Chat interface

[bhf]

Playwright E2E tests currently cover basic navigation but miss key UI interaction paths.

Goal

Implement automated E2E tests for the Command Palette and the AI Assistant Chat in src/app/k8s-dashboard.

Scenarios to Test

• Command Palette: Triggering navigation with :, typing commands (e.g., list pods), and verifying selection results.
• Chat Assistant: Sending a message, verifying the AI response, and checking tool calling integration (if any).
• Keyboard Navigation: Ensure accessibility and keyboard-only dashboard workflows.

Acceptance Criteria

• Add e2e/command-palette.spec.ts.
• Add e2e/chat-integration.spec.ts.
• Ensure that mock models are returned from the /api/models endpoint in E2E.