🎨 Palette: Dynamic Disabled States for Chat Interface Connection

[teerthsharma]

💡 What: Updated the chat input and submit button to be visually disabled when tunnelStatus !== 'LOCKED', utilizing Tailwind's disabled:opacity-50 disabled:cursor-not-allowed utilities. Added dynamic placeholder, aria-label, and title attributes that provide explicit reasoning for the disabled state (e.g. "Disconnected from kernel" or "Connecting to kernel...").

🎯 Why: Previously, the user interface could appear ready for input while the backend tunnel was still initializing or offline, potentially leading to ghost interactions or confusion about why a submission failed. Dynamic tooltips resolve confusion around why a button might be disabled.

📸 Before/After: Visual regression screenshot generated and verified locally to ensure the disabled styling appears correctly when disconnected.

♿ Accessibility: The addition of dynamic aria-label attributes guarantees that screen reader users hear exactly why the chat interface is disabled (e.g., connection lost vs empty input), which represents a major improvement over static or missing attributes. Also ensured the icon-only send button always has an aria-label and title.

---

PR created automatically by Jules for task 5777462564669975890 started by @teerthsharma

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.