feat(storage): support deleting backends and improve admin UI

- Implement storage backend deletion, which automatically resets default storage settings and user-specific overrides when a backend is removed.
- Add unit tests covering the delete action and its cleanup side effects.
- Improve admin UI responsiveness, fixing table scrolling, flex wrapping, and text truncation for long storage backend names.
- Update security documentation to clarify trusted proxy configurations and explain how trusted proxies are protected from automatic bans.

backend/libs/middleware/bans.go

@@ -11,11 +11,15 @@ import (
 func Bans(logger *slog.Logger, bans *services.BanService, trustedProxies []string) Middleware {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			ip := services.ClientIP(r.RemoteAddr, r.Header.Get("X-Forwarded-For"), r.Header.Get("X-Real-IP"), trustedProxies)
-			r = services.WithClientIP(r, ip)
+			ip, ok := services.ClientIPFromContext(r)
+			if !ok {
+				ip = services.ClientIP(r.RemoteAddr, r.Header.Get("X-Forwarded-For"), r.Header.Get("X-Real-IP"), trustedProxies)
+				r = services.WithClientIP(r, ip)
+			}
 			now := time.Now().UTC()
+			protectedProxy := services.IsProtectedProxyIP(ip, trustedProxies)
 
-			if bans != nil {
+			if bans != nil && !protectedProxy {
 				if matched, ok, err := bans.Match(ip, now); err != nil {
 					logger.Error("ban match failed", "source", "ban", "severity", "error", "code", 5001, "ip", ip, "error", err.Error())
 				} else if ok {