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>

internal/api/server.go

@@ -193,16 +193,19 @@ func (s *Server) handleInfo(w http.ResponseWriter, r *http.Request) {
 		"allowed_roots":      s.eng.AllowedRoots(),
 		"default_extensions": engine.DefaultExtensions,
 		"dry_run":            s.st.DryRun(r.Context()),
+		"plex_ignore":        s.st.Setting(r.Context(), "plex_ignore", "0") == "1",
 	})
 }
 
 func (s *Server) handleGetSettings(w http.ResponseWriter, r *http.Request) {
-	writeJSON(w, 200, map[string]any{"dry_run": s.st.DryRun(r.Context())})
+	writeJSON(w, 200, map[string]any{"dry_run": s.st.DryRun(r.Context()),
+		"plex_ignore": s.st.Setting(r.Context(), "plex_ignore", "0") == "1"})
 }
 
 func (s *Server) handlePutSettings(w http.ResponseWriter, r *http.Request) {
 	var body struct {
-		DryRun *bool `json:"dry_run"`
+		DryRun     *bool `json:"dry_run"`
+		PlexIgnore *bool `json:"plex_ignore"`
 	}
 	if !readJSON(w, r, &body) {
 		return
@@ -218,6 +221,19 @@ func (s *Server) handlePutSettings(w http.ResponseWriter, r *http.Request) {
 		}
 		s.log.Info("dry run changed", "dry_run", *body.DryRun)
 	}
+	if body.PlexIgnore != nil {
+		v := "0"
+		if *body.PlexIgnore {
+			v = "1"
+		}
+		if err := s.st.SetSetting(r.Context(), "plex_ignore", v); err != nil {
+			writeErr(w, 500, err)
+			return
+		}
+		results := s.eng.ApplyPlexIgnore(r.Context(), *body.PlexIgnore)
+		writeJSON(w, 200, map[string]any{"dry_run": s.st.DryRun(r.Context()), "plex_ignore": *body.PlexIgnore, "results": results})
+		return
+	}
 	s.handleGetSettings(w, r)
 }