Add a setting to hide the quarantine from Plex

Settings -> Media servers -> "Hide quarantine from Plex" writes a
.plexignore into every pair's quarantine folder (.playlink-trash by
default), with patterns for every folder depth quarantined files live
at. Quarantine folders opened later get the file automatically.

The file carries a marker line: turning the option off removes only
playlink's own file, and an existing .plexignore written by someone else
is never overwritten or deleted (reported instead). Writes go through a
temporary file and a rename.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/api.ts

@@ -33,6 +33,7 @@ export type Info = {
   allowed_roots: string[];
   default_extensions: string[];
   dry_run: boolean;
+  plex_ignore: boolean;
 };
 
 export type Job = {