🚀 feat: Align search API with channel listing & fix sorting toggle

1. Backend
   • `controller/channel.go`
     – Added pagination (`p`, `page_size`) support to `SearchChannels`.
     – Added independent `type` filter (keeps `type_counts` unaffected).
     – Returned `total`, `type_counts` to match `/api/channel/` response.

2. Frontend
   • `ChannelsTable.js`
     – `loadChannels` / `searchChannels` now pass `p`, `page_size`, `id_sort`, `type`, `status` correctly.
     – Pagination, page-size selector and type tabs work for both normal list and search mode.
     – Switch for “ID sort” calls proper API and keeps UI state in sync.
     – Removed unnecessary `normalize` helper; `getFormValues` back to concise form.

Result
• Search mode and normal listing now share identical pagination and filtering behavior.
• Type tabs show correct counts even after searching.
• “ID Sort” toggle no longer inverses actual behaviour.

controller/channel.go

@@ -300,11 +300,51 @@ func SearchChannels(c *gin.Context) {
 		typeCounts[int64(channel.Type)]++
 	}
 
+	typeParam := c.Query("type")
+	typeFilter := -1
+	if typeParam != "" {
+		if tp, err := strconv.Atoi(typeParam); err == nil {
+			typeFilter = tp
+		}
+	}
+
+	if typeFilter >= 0 {
+		filtered := make([]*model.Channel, 0, len(channelData))
+		for _, ch := range channelData {
+			if ch.Type == typeFilter {
+				filtered = append(filtered, ch)
+			}
+		}
+		channelData = filtered
+	}
+
+	page, _ := strconv.Atoi(c.DefaultQuery("p", "1"))
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
+	if page < 1 {
+		page = 1
+	}
+	if pageSize <= 0 {
+		pageSize = 20
+	}
+
+	total := len(channelData)
+	startIdx := (page - 1) * pageSize
+	if startIdx > total {
+		startIdx = total
+	}
+	endIdx := startIdx + pageSize
+	if endIdx > total {
+		endIdx = total
+	}
+
+	pagedData := channelData[startIdx:endIdx]
+
 	c.JSON(http.StatusOK, gin.H{
 		"success": true,
 		"message": "",
 		"data": gin.H{
-			"items":       channelData,
+			"items":       pagedData,
+			"total":       total,
 			"type_counts": typeCounts,
 		},
 	})