feat: implement single binary build and env-based auth

- Unify login page styling with share page
- Add AGENTS.md with build commands and code style guidelines
- Add dev.sh and make.sh for development and production builds
- Implement single binary build with embedded frontend using embed.FS
- Change auth configuration from CLI flag to env variables (USHARE_USERNAME, USHARE_PASSWORD)
- Set default credentials: admin / ushare@123
- Fix static file serving for SPA routes

main.go

@@ -16,10 +16,11 @@ func init() {
 	flag.BoolVar(&opt.Cfg.Debug, "debug", false, "debug mode")
 	flag.StringVar(&opt.Cfg.Address, "address", "0.0.0.0:9119", "")
 	flag.StringVar(&opt.Cfg.DataPath, "data", "/data", "")
-	flag.StringVar(&opt.Cfg.Auth, "auth", "", "auth required(admin, password)")
 	flag.IntVar(&opt.Cfg.CleanInterval, "clean", 24, "清理文件的周期, 单位: 小时, 0 则表示不自动清理")
 	flag.Parse()
 
+	opt.LoadFromEnv()
+
 	if opt.Cfg.Debug {
 		log.SetLogLevel(log.LogLevelDebug)
 		tool.TablePrinter(opt.Cfg)