Move internal packages to an internal folder

For reference: https://go.dev/doc/go1.4#internalpackages

internal/ui/category_refresh.go

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package ui // import "miniflux.app/v2/internal/ui"
+
+import (
+	"net/http"
+
+	"miniflux.app/v2/internal/http/request"
+	"miniflux.app/v2/internal/http/response/html"
+	"miniflux.app/v2/internal/http/route"
+)
+
+func (h *handler) refreshCategoryEntriesPage(w http.ResponseWriter, r *http.Request) {
+	categoryID := h.refreshCategory(w, r)
+	html.Redirect(w, r, route.Path(h.router, "categoryEntries", "categoryID", categoryID))
+}
+
+func (h *handler) refreshCategoryFeedsPage(w http.ResponseWriter, r *http.Request) {
+	categoryID := h.refreshCategory(w, r)
+	html.Redirect(w, r, route.Path(h.router, "categoryFeeds", "categoryID", categoryID))
+}
+
+func (h *handler) refreshCategory(w http.ResponseWriter, r *http.Request) int64 {
+	userID := request.UserID(r)
+	categoryID := request.RouteInt64Param(r, "categoryID")
+
+	jobs, err := h.store.NewCategoryBatch(userID, categoryID, h.store.CountFeeds(userID))
+	if err != nil {
+		html.ServerError(w, r, err)
+		return 0
+	}
+
+	go func() {
+		h.pool.Push(jobs)
+	}()
+
+	return categoryID
+}