v0.8.68: add PTY coverage for work-surface and approval mouse interactions

[Hmbown]

Problem

The PTY suite covers printable-key ownership, Alt help fallback, resize, generic SGR mouse routing, and cancellation, but it does not yet assert the exact mouse and stop-confirm interactions users rely on in the live work surface.

Missing coverage

• Click a concrete live work-surface row and verify the intended selection/action.
• Wheel over the work surface and verify bounded scrolling without changing focus ownership.
• Click and wheel over approval rows, including boundary rows.
• Resize while the work surface or approval surface is active.
• Exercise stop-confirm accept, reject, and repeated-Esc behavior with active work.

Likely files

• crates/tui/tests/qa_pty.rs
• PTY test support/harness modules
• crates/tui/src/tui/mouse_ui.rs
• crates/tui/src/tui/approval.rs
• crates/tui/src/tui/work_surface/

Acceptance criteria

• Tests target real rendered row coordinates rather than only synthetic mouse events.
• Work-surface clicks and wheel events have deterministic ownership.
• Approval-row mouse behavior cannot approve or deny the wrong item.
• Resize preserves the selected item and valid hit regions.
• Stop-confirm tests distinguish canceling the dialog from canceling active work.
• The suite remains stable at 80x24 and 100x32 with one test thread.

[Hmbown]

Resolved by #4361 at merge commit 9bfa466. PTY coverage now exercises real work-surface rows, wheel input, 100x32 to 80x24 resize, stop accept/reject and repeated Escape, plus approval-row wheel/resize/denial with no side effect. The 13-test PTY suite and full hosted macOS/Windows suites are green.