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/reload.go

@@ -3,14 +3,26 @@ package v1
 import (
 	"net/http"
 
+	"github.com/gin-gonic/gin"
+	apitypes "github.com/yusing/go-proxy/internal/api/types"
 	config "github.com/yusing/go-proxy/internal/config/types"
-	"github.com/yusing/go-proxy/internal/net/gphttp"
 )
 
-func Reload(cfg config.ConfigInstance, w http.ResponseWriter, r *http.Request) {
-	if err := cfg.Reload(); err != nil {
-		gphttp.ServerError(w, r, err)
+// @x-id				"reload"
+// @BasePath		/api/v1
+// @Summary		Reload config
+// @Description	Reload config
+// @Tags			v1
+// @Accept			json
+// @Produce		json
+// @Success		200	{object}	apitypes.SuccessResponse
+// @Failure		403	{object}	apitypes.ErrorResponse
+// @Failure		500	{object}	apitypes.ErrorResponse
+// @Router			/reload [post]
+func Reload(c *gin.Context) {
+	if err := config.GetInstance().Reload(); err != nil {
+		c.Error(apitypes.InternalServerError(err, "failed to reload config"))
 		return
 	}
-	gphttp.WriteBody(w, []byte("OK"))
+	c.JSON(http.StatusOK, apitypes.Success("config reloaded"))
 }