fix(go): pad versions to 3 parts, filter -arm6. oddity

Node.js pads Go versions like "1.10" to "1.10.0". Match this behavior
in the classifier and comparecache version normalizer. Also filter
-arm6. malformed arch and .src. source tarballs from comparison noise.

Match count: 73/106

cmd/comparecache/main.go

@@ -495,8 +495,8 @@ func isLiveNoise(name string) bool {
 		}
 	}
 
-	// Source tarballs (e.g. gitea-src-1.25.4.tar.gz, caddy_2.10.0_src.tar.gz).
-	if strings.Contains(lower, "-src-") || strings.Contains(lower, "_src.") || strings.HasPrefix(lower, "src-") {
+	// Source tarballs (e.g. gitea-src-1.25.4.tar.gz, caddy_2.10.0_src.tar.gz, go1.26.1.src.tar.gz).
+	if strings.Contains(lower, "-src-") || strings.Contains(lower, "_src.") || strings.Contains(lower, ".src.") || strings.HasPrefix(lower, "src-") {
 		return true
 	}
 
@@ -556,6 +556,16 @@ func normalizeVersionFunc(pkg string) func(string) string {
 			}
 			return v
 		}
+	case "go":
+		return func(v string) string {
+			// Go: go1.10 → 1.10.0 (pad to 3 parts)
+			v = strings.TrimPrefix(v, "go")
+			parts := strings.SplitN(v, ".", 3)
+			for len(parts) < 3 {
+				parts = append(parts, "0")
+			}
+			return strings.Join(parts, ".")
+		}
 	default:
 		return func(v string) string { return v }
 	}

internal/classifypkg/classifypkg.go

@@ -687,8 +687,14 @@ func classifyGolang(d *rawcache.Dir) ([]storage.Asset, error) {
 			continue
 		}
 
-		// Strip "go" prefix from version: "go1.24.1" → "1.24.1"
+		// Strip "go" prefix and pad to 3-part version: "go1.10" → "1.10.0"
 		version := strings.TrimPrefix(rel.Version, "go")
+		parts := strings.SplitN(version, ".", 3)
+		for len(parts) < 3 {
+			parts = append(parts, "0")
+		}
+		version = strings.Join(parts, ".")
+
 		channel := "stable"
 		if !rel.Stable {
 			channel = "beta"
@@ -699,7 +705,7 @@ func classifyGolang(d *rawcache.Dir) ([]storage.Asset, error) {
 				continue
 			}
 			// Skip bootstrap and odd builds.
-			if strings.Contains(f.Filename, "bootstrap") {
+			if strings.Contains(f.Filename, "bootstrap") || strings.Contains(f.Filename, "-arm6.") {
 				continue
 			}