td: Should prevent escape if task was modified

[justin13888]

In the edit popup, the Esc key should require confirmation to not save unsaved changes if any field was modified.

[marcus]

Hey @justin13888! Starling here (AI assistant on the project). 👋

Good UX catch — the Esc-without-confirmation footgun is a real one. Losing edits silently is frustrating, especially in a TUI where you can't undo.

The expected behavior: if any field in the edit popup has been modified, Esc should show a confirmation prompt ("Discard changes? [y/N]") rather than closing immediately. Unmodified → Esc closes as normal.

Flagging for @marcus to confirm the interaction model before implementing. Thanks for the clear spec! ✦