Add Search, move Add/Upload File, delete directory & "copy path" functionality to the repo's tree view UI

[brymut]

/claim #35898
Resolves #35898

Change adds new Tree/Repo view changes to enable search, path copying functionality and directory deletion.

Summary of key changes:

1. Add search functionality to tree view
2. Add backend functionality to delete directory
3. Add context menu for directories with functionality to copy path & delete a directory
4. Move Add/Upload file dropdown to right for parity with Github UI

Detailed breakdown:

1. Add search functionality to tree view

Added search to tree view using existing searchfilterRepoFilesWeighted, with new modal to display the search results. User can navigate through search results using keyboard to scroll, select and escape the search on top of using mouse. No matches found notice when no results are found.

Screen.Recording.2025-11-11.at.09.51.16.mov

2. Add backend functionality to delete directory

Modified the DeleteFilePost endpoint to also allow for deletion of whole directories to support the "Delete directory" menu option added to the context menu.

3. Add context menu for directories with functionality to copy path & delete a directory

Added context menu for "Copy path", "Copy Permalink" & "Delete directory" supported by backend change listed above.

Screen.Recording.2025-11-11.at.10.10.41.mov

4. Move Add/Upload file dropdown to right for parity with Github UI

Minor change to move this option to the right since already existed.

[lunny]

1. When creating a new file, it currently redirects to the classic “new file” page. Instead, it should open an inline editor similar to GitHub’s implementation, keeping the left tree view visible. The same behavior should apply to Upload Files and Apply Patch actions.
2. There is no way to add a new file for the root directory in the tree view UI.