feat(tui): add working directory actions

[kitlangton]

What

Make the working-directory paths in the prompt and sidebar footers actionable. Clicking either path opens a small menu with:

• Copy path
• Open folder
• Move session

The path brightens on hover, while mouse text selection still takes precedence over opening the menu.

Before / After

Before: The prompt and sidebar footers displayed the current working directory and branch as static text. Copying the underlying absolute path required selecting the truncated label or finding it elsewhere.

After: Clicking the label opens working-directory actions. Copy path uses the full absolute directory and confirms success with a toast.

How

• packages/tui/src/ui/working-directory-actions.tsx owns the shared hover, copy, open, and selection-preservation behavior.
• The prompt and sidebar footer paths each have a stable renderable ID and open the shared action menu on mouse release.
• The sidebar footer slot carries its session ID so both locations can invoke the existing Move session flow.
• A real mouse selection bypasses the menu so copy-on-select behavior remains intact.

Scope

This does not change path abbreviation, footer visibility while a session is running, or existing Move session behavior.

Testing

• bun typecheck in packages/tui
• bun run test in packages/tui (719 passed, 5 skipped)
• Isolated OpenCode Drive run against this checkout:
  • create an isolated session at a wide viewport
  • semantic click on sidebar.footer.location
  • wait for the Working directory menu
  • select Copy path
  • wait for the clipboard confirmation toast

Demo

OpenCode Drive running an isolated project against this checkout:

recording-2ed90a49-d86a-4afa-9991-363c85b92589.mp4