fix: address code review findings

- Honor ignore_singles/ignore_compilations at scanner read time so toggles
  take effect immediately on the dashboard, artist page, and digest instead
  of waiting for the MusicBrainz cache to expire and prune rows.
- Run notifier notify synchronously in the scheduler loop to avoid overlapping
  read-send-mark runs double-sending the digest.
- Show artist name (with ID fallback) on the archive page instead of raw IDs.
- Select last_synced in GetAllArtistSettings for contract consistency.
- Fix stale startPeriodicSync comment and remove redundant error var.
- Remove dead ignored-branch from the artist template (never rendered).
- Add tests: CSRF sameOrigin, ArtistCacheFresh, secondary_types round-trip,
  and scanner type-toggle filtering.
- Update Specification.md schema/config to reflect mbid, last_synced,
  secondary_types, sync.interval, and server.public_url.

internal/web/handlers.go

@@ -68,6 +68,7 @@ type LocalAlbumView struct {
 // artist detail page, including the ignore toggle form target.
 type MissingReleaseView struct {
 	ArtistID    string
+	ArtistName  string
 	RGID        string
 	Title       string
 	Type        string
@@ -189,14 +190,18 @@ func (s *Server) handleArchive(w http.ResponseWriter, r *http.Request) {
 
 	data := &ArchiveData{UIBaseURL: s.uiBaseURL}
 	for _, rel := range ignored {
-		data.Releases = append(data.Releases, MissingReleaseView{
+		view := MissingReleaseView{
 			ArtistID:    rel.ArtistID,
 			RGID:        rel.RGID,
 			Title:       rel.Title,
 			Type:        rel.Type,
 			ReleaseDate: rel.ReleaseDate,
 			Ignored:     true,
-		})
+		}
+		if settings, err := database.GetArtistSettings(s.db, rel.ArtistID); err == nil {
+			view.ArtistName = settings.Name
+		}
+		data.Releases = append(data.Releases, view)
 	}
 
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
@@ -271,8 +276,7 @@ func (s *Server) ignoreOrRestore(w http.ResponseWriter, r *http.Request) {
 		// A 0-rows-affected error means the release was already removed by a
 		// concurrent re-sync (it disappeared from MusicBrainz). That is benign:
 		// redirect back rather than surfacing a 500 for a now-nonexistent row.
-		var notFoundErr error = database.ErrReleaseNotFound
-		if errors.Is(err, notFoundErr) {
+		if errors.Is(err, database.ErrReleaseNotFound) {
 			http.Redirect(w, r, "/artist/"+id, http.StatusSeeOther)
 			return
 		}