增加公告图片编辑, 增加取消归档

backend/internal/modules/file/handler.go

@@ -65,7 +65,7 @@ func (h *Handler) writeObject(c *gin.Context, publicOnly bool) {
 		response.BadRequest(c, "文件 key 不正确")
 		return
 	}
-	if publicOnly && !strings.HasPrefix(key, "home-banner/") && !strings.HasPrefix(key, "avatar/") && !strings.HasPrefix(key, "payment-cert/") {
+	if publicOnly && !strings.HasPrefix(key, "home-banner/") && !strings.HasPrefix(key, "avatar/") && !strings.HasPrefix(key, "payment-cert/") && !strings.HasPrefix(key, "announcement/") {
 		response.Error(c, http.StatusNotFound, "not_found", "文件不存在或暂不可访问")
 		return
 	}

backend/internal/modules/file/service.go

@@ -106,7 +106,7 @@ func normalizeContentType(contentType string, data []byte) string {
 
 func fileURLForScene(scene string, key string) string {
 	fileURL := "/api/files/object?key=" + url.QueryEscape(key)
-	if scene == "home-banner" || scene == "avatar" || scene == "payment-cert" {
+	if scene == "home-banner" || scene == "avatar" || scene == "payment-cert" || scene == "announcement" {
 		fileURL = "/api/public/files/object?key=" + url.QueryEscape(key)
 	}
 	return fileURL
@@ -115,7 +115,7 @@ func fileURLForScene(scene string, key string) string {
 func normalizeScene(scene string) string {
 	scene = strings.TrimSpace(strings.ToLower(scene))
 	switch scene {
-	case "listing", "handoff", "dispute", "realname", "avatar", "home-banner", "chat", "payment-cert":
+	case "listing", "handoff", "dispute", "realname", "avatar", "home-banner", "chat", "payment-cert", "announcement":
 		return scene
 	default:
 		return "misc"

backend/internal/modules/file/storage_test.go

@@ -1,6 +1,9 @@
 package file
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestSanitizeObjectMetadataEscapesNonASCII(t *testing.T) {
 	got := sanitizeObjectMetadata(map[string]string{
@@ -11,3 +14,18 @@ func TestSanitizeObjectMetadataEscapesNonASCII(t *testing.T) {
 		t.Fatalf("metadata filename = %q", got["original-filename"])
 	}
 }
+
+func TestAnnouncementSceneUsesPublicFileURL(t *testing.T) {
+	key := "announcement/2026/06/15/example.webp"
+	got := fileURLForScene("announcement", key)
+
+	if !strings.HasPrefix(got, "/api/public/files/object?") {
+		t.Fatalf("announcement file url = %q, want public file endpoint", got)
+	}
+}
+
+func TestNormalizeSceneAllowsAnnouncement(t *testing.T) {
+	if got := normalizeScene("announcement"); got != "announcement" {
+		t.Fatalf("normalize announcement scene = %q", got)
+	}
+}