feat:add context interface, and change core.writeresponse function to use it

internal/pkg/core/context.go

@@ -0,0 +1,5 @@
+package core
+
+type Context interface {
+	JSON(code int, obj any)
+}

internal/pkg/core/core.go

@@ -26,7 +26,6 @@ import (
 	"net/http"
 
 	"git.vinchent.xyz/vinchent/howmuch/internal/pkg/errno"
-	"github.com/gin-gonic/gin"
 )
 
 type ErrResponse struct {
@@ -36,7 +35,7 @@ type ErrResponse struct {
 
 // WriteResponse writes the response to the HTTP response writer with HTTP code
 // and potential errors.
-func WriteResponse(c *gin.Context, err error, data any) {
+func WriteResponse(c Context, err error, data any) {
 	// No error, write json response directly
 	if err == nil {
 		c.JSON(http.StatusOK, data)