fix(naming): strip unsubstituted Sonarr tokens ({TvdbId}/{imdb-}) from titles

These tokens survived the provider-tag regex ([\w]+ doesn't match braces),
polluting parsed titles (e.g. 'A Girl & Her Guard Dog [tvdb-{TvdbId}]') so
they could not score-match. Broaden the regex to drop {...} and empty tokens.

internal/naming/provider_token_test.go

@@ -0,0 +1,25 @@
+package naming
+
+import "testing"
+
+func TestStripInferProviderTags_HandlesBrokenSonarrTokens(t *testing.T) {
+	cases := []struct {
+		in   string
+		want string
+	}{
+		{"A Girl & Her Guard Dog [tvdb-{TvdbId}]", "A Girl & Her Guard Dog"},
+		{"A Raven in the Harem [tvdb-{TvdbId}]", "A Raven in the Harem"},
+		{"A Salad Bowl of Eccentrics {imdb-}", "A Salad Bowl of Eccentrics"},
+		{"Coronation Street {imdb-}", "Coronation Street"},
+		// well-formed tags must still be stripped:
+		{"Some Show [tvdb-81189]", "Some Show"},
+		{"Some Show {tmdb-27205}", "Some Show"},
+		// no tag: unchanged:
+		{"Cowboy Bebop", "Cowboy Bebop"},
+	}
+	for _, c := range cases {
+		if got := stripInferProviderTags(c.in); got != c.want {
+			t.Errorf("stripInferProviderTags(%q) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}

internal/naming/root_inference.go

@@ -18,7 +18,10 @@ var (
 	inferSeasonDirRe       = regexp.MustCompile(`(?i)^Season\s+(\d{1,4})(?:\s.*)?$`)
 	inferNumericSeasonRe   = regexp.MustCompile(`^\d{1,4}$`)
 	inferSpecialsDirRe     = regexp.MustCompile(`(?i)^(?:specials?|extras?)$`)
-	inferProviderTagRe     = regexp.MustCompile(`\s*[{\[](?:tmdb|tmdbid|imdb|imdbid|tvdb|tvdbid)-[\w]+[}\]]`)
+	// Matches a well-formed tag ([tvdb-81189]), an unsubstituted Sonarr token
+	// ([tvdb-{TvdbId}]), or an empty token ({imdb-}). The id part is either a
+	// {...} placeholder or zero-or-more word chars.
+	inferProviderTagRe     = regexp.MustCompile(`\s*[{\[](?:tmdb|tmdbid|imdb|imdbid|tvdb|tvdbid)-(?:\{[^}]*\}|[\w]*)[}\]]`)
 )
 
 type RootAssignment struct {