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/httpserver/server.go

@@ -49,6 +49,7 @@ func New(cfg config.Config, logger *slog.Logger) (*http.Server, error) {
 		middleware.RequestID,
 		middleware.SecurityHeaders,
 		middleware.Gzip,
+		middleware.ClientIP(cfg.TrustedProxies),
 		middleware.Logger(logger),
 		middleware.Bans(logger, banService, cfg.TrustedProxies),
 	)