feat(ui): add message cache management page and dashboard enhancements

- Introduced MessageCachePage for browsing and managing cached webhook events.
- Enhanced DashboardPage to display runtime stats and message cache information.
- Added new API types for message cache events and system stats.
- Integrated SwaggerPage for API documentation and live request testing.

pkg/handlers/cache.go

@@ -25,17 +25,60 @@ func (h *Handlers) GetCachedEvents(w http.ResponseWriter, r *http.Request) {
 
 	// Optional event_type filter
 	eventType := r.URL.Query().Get("event_type")
+	limit := 0
+	offset := 0
+	limitProvided := false
+	offsetProvided := false
 
-	var cachedEvents interface{}
-	if eventType != "" {
-		cachedEvents = cache.ListByEventType(events.EventType(eventType))
-	} else {
-		cachedEvents = cache.List()
+	limitParam := r.URL.Query().Get("limit")
+	if limitParam != "" {
+		parsedLimit, err := strconv.Atoi(limitParam)
+		if err != nil {
+			http.Error(w, "Invalid limit parameter", http.StatusBadRequest)
+			return
+		}
+		if parsedLimit <= 0 {
+			http.Error(w, "Limit must be greater than 0", http.StatusBadRequest)
+			return
+		}
+		limit = parsedLimit
+		limitProvided = true
+	}
+
+	offsetParam := r.URL.Query().Get("offset")
+	if offsetParam != "" {
+		parsedOffset, err := strconv.Atoi(offsetParam)
+		if err != nil {
+			http.Error(w, "Invalid offset parameter", http.StatusBadRequest)
+			return
+		}
+		if parsedOffset < 0 {
+			http.Error(w, "Offset must be greater than or equal to 0", http.StatusBadRequest)
+			return
+		}
+		offset = parsedOffset
+		offsetProvided = true
+	}
+
+	// If offset is provided without limit, use a sensible page size.
+	if offsetProvided && !limitProvided {
+		limit = 100
+	}
+
+	cachedEvents, filteredCount := cache.ListPaged(events.EventType(eventType), limit, offset)
+	if !limitProvided && !offsetProvided {
+		// Backward-compatible response values when pagination is not requested.
+		limit = len(cachedEvents)
+		offset = 0
 	}
 
 	writeJSON(w, map[string]interface{}{
 		"cached_events": cachedEvents,
 		"count":         cache.Count(),
+		"filtered_count": filteredCount,
+		"returned_count": len(cachedEvents),
+		"limit":          limit,
+		"offset":         offset,
 	})
 }