feat(security): add trusted proxies and abuse event cleanup

- Add `WARPBOX_TRUSTED_PROXIES` configuration to restrict accepted forwarded client IP headers to specific proxy IPs/CIDRs, securing client IP resolution.
- Integrate `BanService` into the background cleanup job to automatically purge expired abuse and ban evidence events.
- Update documentation with reverse proxy security guidelines and a production systemd deployment guide.

backend/libs/handlers/upload.go

@@ -18,6 +18,7 @@ import (
 func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 	user, loggedIn, authErr := a.currentUserWithAuthError(r)
 	if authErr != nil {
+		a.logger.Warn("upload rejected invalid bearer token", "source", "user-upload", "severity", "warn", "code", 4010, "ip", uploadClientIP(r), "user_agent", r.UserAgent())
 		helpers.WriteJSONError(w, http.StatusUnauthorized, "invalid bearer token")
 		return
 	}
@@ -29,12 +30,14 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if !loggedIn && !settings.AnonymousUploadsEnabled {
+		a.logger.Warn("anonymous upload rejected disabled", "source", "user-upload", "severity", "warn", "code", 4012, "ip", uploadClientIP(r))
 		helpers.WriteJSONError(w, http.StatusForbidden, "anonymous uploads are disabled")
 		return
 	}
 	effectivePolicy := a.effectiveUploadPolicy(settings, user, loggedIn)
 	rateKey := uploadRateKey(r, user, loggedIn)
 	if !isAdminUpload && !a.rateLimiter.Allow("upload:"+rateKey, effectivePolicy.ShortRequests, effectivePolicy.ShortWindow, time.Now().UTC()) {
+		a.logger.Warn("upload rate limited", "source", "user-upload", "severity", "warn", "code", 4290, "ip", uploadClientIP(r), "user_id", user.ID)
 		helpers.WriteJSONError(w, http.StatusTooManyRequests, "too many upload requests, please slow down")
 		return
 	}
@@ -49,6 +52,7 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		parseLimit = 32 << 20
 	}
 	if err := r.ParseMultipartForm(parseLimit); err != nil {
+		a.logger.Warn("upload form parse failed", "source", "user-upload", "severity", "warn", "code", 4000, "ip", uploadClientIP(r), "user_id", user.ID, "error", err.Error())
 		helpers.WriteJSONError(w, http.StatusBadRequest, "upload form could not be read")
 		return
 	}
@@ -61,12 +65,14 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		ownerID = user.ID
 		collectionID = r.FormValue("collection_id")
 		if !a.authService.CollectionOwnedBy(collectionID, user.ID) {
+			a.logger.Warn("upload rejected invalid collection", "source", "user-upload", "severity", "warn", "code", 4030, "user_id", user.ID, "collection_id", collectionID)
 			helpers.WriteJSONError(w, http.StatusForbidden, "collection not found")
 			return
 		}
 	}
 	if !isAdminUpload {
 		if status, message := a.checkUploadPolicy(r, user, loggedIn, settings, effectivePolicy, files, totalBytes); message != "" {
+			a.logger.Warn("upload rejected by policy", "source", "quota", "severity", "warn", "code", status, "ip", uploadClientIP(r), "user_id", user.ID, "message", message, "bytes", totalBytes, "files", len(files))
 			helpers.WriteJSONError(w, status, message)
 			return
 		}
@@ -76,11 +82,13 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		maxDays = min(7, effectivePolicy.MaxDays)
 	}
 	if !isAdminUpload && maxDays > effectivePolicy.MaxDays {
+		a.logger.Warn("upload rejected expiration days", "source", "user-upload", "severity", "warn", "code", 4131, "ip", uploadClientIP(r), "user_id", user.ID, "requested_days", maxDays, "max_days", effectivePolicy.MaxDays)
 		helpers.WriteJSONError(w, http.StatusRequestEntityTooLarge, fmt.Sprintf("expiration cannot exceed %d days", effectivePolicy.MaxDays))
 		return
 	}
 	expiresMinutes := parseInt(r.FormValue("expires_minutes"))
 	if expiresMinutes > 0 && !isAdminUpload && expiresMinutes > effectivePolicy.MaxDays*24*60 {
+		a.logger.Warn("upload rejected expiration minutes", "source", "user-upload", "severity", "warn", "code", 4132, "ip", uploadClientIP(r), "user_id", user.ID, "requested_minutes", expiresMinutes, "max_days", effectivePolicy.MaxDays)
 		helpers.WriteJSONError(w, http.StatusRequestEntityTooLarge, fmt.Sprintf("expiration cannot exceed %d days", effectivePolicy.MaxDays))
 		return
 	}
@@ -97,7 +105,7 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		StorageBackendID:  effectivePolicy.StorageBackendID,
 	})
 	if err != nil {
-		a.logger.Warn("upload failed", "source", "user-upload", "severity", "warn", "code", 4001, "error", err.Error())
+		a.logger.Warn("upload failed", "source", "user-upload", "severity", "warn", "code", 4001, "ip", uploadClientIP(r), "user_id", user.ID, "error", err.Error())
 		helpers.WriteJSONError(w, http.StatusBadRequest, err.Error())
 		return
 	}
@@ -110,6 +118,7 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 	jobs.GenerateThumbnailsForBoxAsync(a.uploadService, a.logger, result.BoxID)
+	a.logger.Info("upload response sent", "source", "user-upload", "severity", "user_activity", "code", 2001, "ip", uploadClientIP(r), "user_id", user.ID, "box_id", result.BoxID, "files", len(files), "bytes", totalBytes, "admin", isAdminUpload)
 
 	if wantsJSON(r) {
 		helpers.WriteJSON(w, http.StatusCreated, result)
@@ -235,7 +244,10 @@ func uploadParseLimit(policy services.EffectiveUploadPolicy, loggedIn bool, fall
 }
 
 func uploadClientIP(r *http.Request) string {
-	return services.ClientIP(r.RemoteAddr, r.Header.Get("X-Forwarded-For"))
+	if ip, ok := services.ClientIPFromContext(r); ok {
+		return ip
+	}
+	return services.ClientIP(r.RemoteAddr, r.Header.Get("X-Forwarded-For"), r.Header.Get("X-Real-IP"), nil)
 }
 
 func uploadRateKey(r *http.Request, user services.User, loggedIn bool) string {