Add wildcard and regex modes to Bulk Rename

Plain-text substring matching couldn't handle a batch of
slightly-different patterns (e.g. several release-group suffixes) in
one pass. Add a match-type selector: wildcard (shell-style */?) for
the common case, and full regex (with backreferences in the
replacement) for anything more precise. Invalid regex is caught and
reported inline instead of failing the request.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -116,7 +116,11 @@ silently stay blank instead of erroring.
   for when files were added/removed directly on disk.
   - *Bulk Rename*: find & replace across every course/folder name in the
   library at once, with a per-match preview and the ability to drop
-  individual matches before applying.
+  individual matches before applying. Three match modes: plain text
+  (default, literal substring), wildcard (shell-style `*`/`?`, e.g.
+  `.BOOKWARE*` catches `.BOOKWARE-GETH`, `.BOOKWARE-BOOKTIME`,
+  `.BOOKWARE-BLZiSO`, etc. in one pass), or full regex (with
+  backreferences in the replacement, e.g. `\1`).
   - *Manage Library*: hide courses/folders from the browser without
   touching anything on disk (hiding a folder hides everything inside it;
   bulk-select elsewhere to hide or queue several at once), rename a