refactor(api): restructured API for type safety, maintainability and docs generation

- These changes makes the API incombatible with previous versions
- Added new types for error handling, success responses, and health checks.
- Updated health check logic to utilize the new types for better clarity and structure.
- Refactored existing handlers to improve response consistency and error handling.
- Updated Makefile to include a new target for generating API types from Swagger.
- Updated "new agent" API to respond an encrypted cert pair

internal/api/v1/icons.go

@@ -0,0 +1,37 @@
+package v1
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	apitypes "github.com/yusing/go-proxy/internal/api/types"
+	"github.com/yusing/go-proxy/internal/homepage"
+)
+
+type ListIconsRequest struct {
+	Limit   int    `form:"limit" validate:"omitempty,min=0"`
+	Keyword string `form:"keyword" validate:"required"`
+} //	@name	ListIconsRequest
+
+// @x-id				"icons"
+// @BasePath		/api/v1
+// @Summary		List icons
+// @Description	List icons
+// @Tags			v1
+// @Accept			json
+// @Produce		json
+// @Param			limit	query		int		false	"Limit"
+// @Param			keyword	query		string	false	"Keyword"
+// @Success		200		{array}		homepage.IconMetaSearch
+// @Failure		400		{object}	apitypes.ErrorResponse
+// @Failure		403		{object}	apitypes.ErrorResponse
+// @Router			/icons [get]
+func Icons(c *gin.Context) {
+	var request ListIconsRequest
+	if err := c.ShouldBindQuery(&request); err != nil {
+		c.JSON(http.StatusBadRequest, apitypes.Error("invalid request", err))
+		return
+	}
+	icons := homepage.SearchIcons(request.Keyword, request.Limit)
+	c.JSON(http.StatusOK, icons)
+}