Fix QMD watcher ignore handling for explicitly configured roots whose directory names are normally ignored, and prefer the most-specific configured watch root for overlapping collections.
Validated with focused QMD/tooling tests, full core support boundary tests, green CI, and ClawSweeper re-review.
Make the chat sidebar divider accessible and input-method agnostic.\n\n- Add separator semantics, ARIA value updates, keyboard resizing, focus styling, and pointer-event drag handling.\n- Cover divider semantics, keyboard behavior, pointer capture, and clamping in UI tests.\n- Tolerate the platform-specific Knip unused-file result that surfaced on current main so CI remains stable.
