fix: address code review findings

- notifier: show artist display names (not internal IDs) in digest; resolve
  names from artist_settings and fall back to ID when unavailable
- notifier: skip sending an empty digest to avoid daily spam
- config: require telegram token/chat_id when enabled
- web: warn loudly when auth is disabled on a non-loopback bind; add HTTP
  server timeouts
- web: treat SetReleaseIgnored "release not found" as benign redirect (0 rows)
- musicbrainz: reject low-score/name-mismatched MBID resolutions instead of
  silently caching the wrong artist
- database: remove dead duplicate err check; harden DSN param appending
- musicbrainz: check rows.Err() after iterating existing releases

internal/web/handlers.go

@@ -3,6 +3,7 @@ package web
 import (
 	"context"
 	"embed"
+	"errors"
 	"fmt"
 	"html/template"
 	"net/http"
@@ -238,6 +239,14 @@ func (s *Server) ignoreOrRestore(w http.ResponseWriter, r *http.Request) {
 
 	ignored := action == "ignore"
 	if err := database.SetReleaseIgnored(s.db, rgid, ignored); err != nil {
+		// 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) {
+			http.Redirect(w, r, "/artist/"+id, http.StatusSeeOther)
+			return
+		}
 		http.Error(w, fmt.Sprintf("failed to set ignored: %v", err), http.StatusInternalServerError)
 		return
 	}

internal/web/server.go

@@ -44,6 +44,13 @@ func NewServer(cfg *config.ServerConfig, db *database.DB, uiBaseURL string, thre
 		uiBaseURL: strings.TrimRight(uiBaseURL, "/"),
 		threshold: threshold,
 	}
+	// Warn loudly when auth is disabled but the server is reachable from outside
+	// the host: Basic auth is silently skipped when Username/Password are empty,
+	// so an operator who forgets credentials on a non-loopback bind would expose
+	// DB-mutating POST routes (ignore/restore/toggle) to the network.
+	if (cfg.Username == "" || cfg.Password == "") && cfg.Host != "localhost" && cfg.Host != "127.0.0.1" && cfg.Host != "::1" {
+		log.Printf("WARNING: Web UI authentication is DISABLED (server.username/password empty) and the server is bound to %q. The dashboard and its state-changing routes are exposed to the network. Set credentials or bind to localhost.", cfg.Host)
+	}
 	mux := http.NewServeMux()
 	mux.HandleFunc("/", s.handleDashboard)
 	mux.HandleFunc("/artist/{id}", s.handleArtist)
@@ -72,8 +79,12 @@ func (s *Server) Addr() string {
 // due to ctx cancellation returns nil).
 func (s *Server) Start(ctx context.Context) error {
 	srv := &http.Server{
-		Addr:    s.Addr(),
-		Handler: s.Handler(),
+		Addr:              s.Addr(),
+		Handler:           s.Handler(),
+		ReadTimeout:       15 * time.Second,
+		ReadHeaderTimeout: 10 * time.Second,
+		WriteTimeout:      30 * time.Second,
+		IdleTimeout:       120 * time.Second,
 	}
 
 	go func() {