fix(library): classify resolution by width + height, not height alone

Cinematic widescreen content (1920×804 at 2.39:1, 3840×1600 21:9, etc.)
was being misclassified: a 1080p source presented as 1920×804 fell to
720p because 804 < 900. Same shape for 2160p sources letterboxed below
2000px tall.

ResolveResolution now takes (width, height) and picks the larger of the
width-derived and height-derived buckets, so anamorphic/letterboxed
sources land in the right bucket.

internal/cmd/scan.go

@@ -241,7 +241,7 @@ func printScanSummary(cache *library.LibraryCache) {
 			continue
 		}
 
-		res := library.ResolveResolution(item.MediaInfo.Video.Height)
+		res := library.ResolveResolution(item.MediaInfo.Video.Width, item.MediaInfo.Video.Height)
 		if res == "" {
 			res = "other"
 		}

internal/library/resolve.go

@@ -13,8 +13,17 @@ var (
 	altEpRegex  = regexp.MustCompile(`(?i)(\d{1,2})x(\d{2})`)
 )
 
-// ResolveResolution maps a pixel height to a standard resolution label.
-func ResolveResolution(height int) string {
+// ResolveResolution maps video dimensions to a standard resolution label.
+// Uses both width and height so cinematic aspect ratios (2.35:1, 2.39:1, 21:9)
+// are not misclassified — e.g. a 1080p source presented as 1920×804 letterboxed
+// would fall to 720p if classified by height alone.
+func ResolveResolution(width, height int) string {
+	byHeight := resolutionByHeight(height)
+	byWidth := resolutionByWidth(width)
+	return maxResolution(byHeight, byWidth)
+}
+
+func resolutionByHeight(height int) string {
 	switch {
 	case height >= 2000:
 		return "2160p"
@@ -29,6 +38,36 @@ func ResolveResolution(height int) string {
 	}
 }
 
+func resolutionByWidth(width int) string {
+	switch {
+	case width >= 3400:
+		return "2160p"
+	case width >= 1800:
+		return "1080p"
+	case width >= 1200:
+		return "720p"
+	case width >= 800:
+		return "480p"
+	default:
+		return ""
+	}
+}
+
+var resolutionRank = map[string]int{
+	"":      0,
+	"480p":  1,
+	"720p":  2,
+	"1080p": 3,
+	"2160p": 4,
+}
+
+func maxResolution(a, b string) string {
+	if resolutionRank[a] >= resolutionRank[b] {
+		return a
+	}
+	return b
+}
+
 // DeriveContentType guesses "movie" or "show" from parsed metadata.
 func DeriveContentType(item LibraryItem) string {
 	if item.Season > 0 || item.Episode > 0 {

internal/library/resolve_test.go

@@ -8,28 +8,31 @@ import (
 
 func TestResolveResolution(t *testing.T) {
 	tests := []struct {
+		name   string
+		width  int
 		height int
 		want   string
 	}{
-		{2160, "2160p"},
-		{2000, "2160p"},
-		{1080, "1080p"},
-		{1920, "1080p"}, // 1920 is width, not height — height for 1080p is ~1080
-		{900, "1080p"},
-		{720, "720p"},
-		{600, "720p"},
-		{576, "480p"},
-		{480, "480p"},
-		{400, "480p"},
-		{360, ""},
-		{0, ""},
+		{"4K square", 3840, 2160, "2160p"},
+		{"4K low height", 3840, 1600, "2160p"},
+		{"1080p square", 1920, 1080, "1080p"},
+		{"1080p cinematic 2.39:1", 1920, 804, "1080p"}, // anamorphic widescreen — must not fall to 720p
+		{"1080p cinematic 2.35:1", 1920, 818, "1080p"},
+		{"1080p 21:9", 2560, 1080, "1080p"},
+		{"720p square", 1280, 720, "720p"},
+		{"720p widescreen", 1280, 540, "720p"},
+		{"480p", 854, 480, "480p"},
+		{"sub-480", 640, 360, ""},
+		{"zero", 0, 0, ""},
 	}
 
 	for _, tt := range tests {
-		got := ResolveResolution(tt.height)
-		if got != tt.want {
-			t.Errorf("ResolveResolution(%d) = %q, want %q", tt.height, got, tt.want)
-		}
+		t.Run(tt.name, func(t *testing.T) {
+			got := ResolveResolution(tt.width, tt.height)
+			if got != tt.want {
+				t.Errorf("ResolveResolution(%d, %d) = %q, want %q", tt.width, tt.height, got, tt.want)
+			}
+		})
 	}
 }
 

internal/library/sync.go

@@ -23,7 +23,7 @@ func BuildSyncItems(cache *LibraryCache) []agent.LibrarySyncItem {
 
 		if item.MediaInfo != nil {
 			if item.MediaInfo.Video != nil {
-				si.Resolution = ResolveResolution(item.MediaInfo.Video.Height)
+				si.Resolution = ResolveResolution(item.MediaInfo.Video.Width, item.MediaInfo.Video.Height)
 				si.VideoCodec = item.MediaInfo.Video.Codec
 				si.HDR = item.MediaInfo.Video.HDR
 				si.BitDepth = item.MediaInfo.Video.BitDepth