[ZEPPELIN-6345] Fire NoteRemove event for each note when deleting a folder

[HwangRock]

What is this PR for?

Deleting a folder left its notes searchable after removal. removeFolder(String, AuthenticationInfo) in Notebook called noteManager.removeFolder first, which detached the notes from the tree, so the following removeNote(noteId) loaded a null note and skipped fireNoteRemoveEvent. SearchService.deleteNoteIndex was therefore never invoked and the Lucene search index kept stale documents for the deleted notes, so they still showed up in search results after emptying the trash or removing a folder.

This PR loads the notes non-destructively via a new NoteManager.getNoteInfoRecursively, runs the same per-note cleanup as removeNote(Note, AuthenticationInfo) (setRemoved, removeNoteAuth, fireNoteRemoveEvent) for each note, and only then deletes the folder. This also removes the pre-existing NotebookRepo.remove is called twice TODO, since the repo remove now happens once.

What type of PR is it?

Bug Fix

What is the Jira issue?

• https://issues.apache.org/jira/browse/ZEPPELIN-6345

Screenshots (if appropriate)

2026-07-12.5.44.20.mov

How should this be tested?

• Added NotebookTest#testRemoveFolderFiresNoteRemoveEventForEachNote: creates two notes under /folder1, registers a NoteEventListener counting onNoteRemove, calls removeFolder("/folder1", ...), and asserts the event fired once per note. Fails before the change (count 0), passes after.
• Manual: create notes, move them to trash, empty the trash, then search for a deleted note. Before the fix it still appears in results; after the fix it is gone.

Questions:

• Does the license files need to update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No

[hyunw9]

LGTM :)

[ParkGyeongTae]

LGTM. The root cause analysis is accurate — moving noteManager.removeFolder()
to after the per-note cleanup ensures processNote() can still find each note
in notesInfo and fire NoteRemoveEvent correctly.

While reviewing this, I noticed that removeFolder does not evict note cache
entries via noteCache.removeNote(), which is a pre-existing issue unrelated
to this fix. I've filed a separate Jira ticket for it — feel free to take a
look if you're interested.
https://issues.apache.org/jira/projects/ZEPPELIN/issues/ZEPPELIN-6529

[HwangRock]

@ParkGyeongTae Thanks for filing ZEPPELIN-6529 and letting me know! Confirmed the bug and sent a PR here: #5296

[ParkGyeongTae]

Thanks for the quick follow-up! I'll take a look at #5296.

[ParkGyeongTae]

Merged into master (0c4b30f).