fix: address code review findings

internal/normalize/normalize.go

@@ -18,6 +18,10 @@ var (
 	parenRe   = regexp.MustCompile(`\([^)]*\)`)
 	yearRe    = regexp.MustCompile(`\b(1[0-9]{3}|2[0-9]{3})\b`)
 	spaceRe   = regexp.MustCompile(`\s+`)
+	// wordRe matches any alphabetic character. Used to decide whether a title
+	// that collapses entirely to a year actually had other words worth keeping
+	// (e.g. "1989 (Deluxe)") versus being a bare year title (e.g. "1989").
+	wordRe = regexp.MustCompile(`[a-z]`)
 )
 
 // NormalizeString normalizes a string for fuzzy matching by:
@@ -28,6 +32,10 @@ var (
 //   - Collapsing multiple spaces into one
 //   - Trimming leading/trailing whitespace
 func NormalizeString(s string) string {
+	// Capture the original input; used after stripping to tell a bare year
+	// title apart from a title that merely collapses to a year.
+	original := s
+
 	// Convert to lowercase
 	s = strings.ToLower(s)
 
@@ -37,11 +45,23 @@ func NormalizeString(s string) string {
 	// Remove parenthesized content (e.g., (Deluxe), (Remastered))
 	s = parenRe.ReplaceAllString(s, "")
 
-	// Remove years (4-digit numbers between 1000-2999). If stripping the
-	// year would empty the entire string (e.g. an album literally titled
-	// "1989" or "2112"), keep the original form so the title can still match.
+	// Remove years (4-digit numbers between 1000-2999). If stripping the year
+	// would empty the entire string, we must decide what to keep:
+	//   - A bare year title (e.g. "1989", "2112") has no other words, so keep
+	//     the year so it can still match itself (the user owns that album).
+	//   - A title that had OTHER words alongside the year (e.g. "1989 (Deluxe)")
+	//     collapses to empty on purpose: it is a distinct release group that
+	//     must NOT be considered already-present just because the user owns the
+	//     standard "1989". Collapsing to empty makes it score 0.0 against a
+	//     plain "1989", correctly reporting the reissue as missing.
 	stripped := yearRe.ReplaceAllString(s, "")
-	if strings.TrimSpace(stripped) != "" {
+	if strings.TrimSpace(stripped) == "" {
+		if wordRe.MatchString(strings.ToLower(original)) {
+			s = ""
+		} else {
+			s = strings.TrimSpace(s)
+		}
+	} else {
 		s = stripped
 	}