fix: infer macOS from .app.zip/.dmg, filter npm tarballs and .d.ts

- .app.zip and .dmg formats now infer darwin OS when absent
- Filter .tgz (npm packages) and .d.ts (TypeScript defs) as meta-assets
- Reduces bun false positives by 64, deno by 294

internal/classify/classify.go

@@ -54,6 +54,10 @@ func Filename(name string) Result {
 	if os == "" && (format == buildmeta.FormatDeb || format == buildmeta.FormatRPM) {
 		os = buildmeta.OSLinux
 	}
+	// .app.zip and .dmg are macOS-only formats.
+	if os == "" && (format == buildmeta.FormatAppZip || format == buildmeta.FormatDMG) {
+		os = buildmeta.OSDarwin
+	}
 
 	return Result{
 		OS:     os,