#2913 gatorwalk-factory studio: a replaced directory that gets the same inode number is still not watched again

Follow-up to #2841. The studio watch (gatorwalk-factory/extensions/models/_lib/engine/studio_watch.ts) now detects a watched directory that was deleted and made again by comparing the directory's inode number between relists. On ext4 and XFS, rm -rf models && mkdir models can give the new directory the same inode number. The old watch is then kept: it stays on the deleted directory and sees nothing, so live reload stops for every factory in it until the page reloads. Where stat gives no inode, replacement is never detected.

Suggested fix: when a watch reports a remove event whose path is the watched directory itself (inotify reports this; seen in the #2841 probe), mark that watch dead, so the next relist replaces it whatever the inode says. Keep the inode check as a backstop.

Also from the #2841 reviews: the replaced-directory test in integration/engine/studio_watch_test.ts can pass its first assertion on the old watch's event for the deleted file. Tighten it so that only the new path can satisfy it. The tests run on tmpfs, which did not reuse the inode number.