Add manual cloud backup controls and manager modal

ui/panel.html

@@ -1072,6 +1072,74 @@
                 </label>
               </div>
 
+              <div class="bme-config-card" style="margin-top: 20px;">
+                <div class="bme-config-card-head">
+                  <div>
+                    <div class="bme-config-card-title">云端存储模式</div>
+                    <div class="bme-config-card-subtitle">
+                      自动模式沿用当前镜像同步；手动模式停止自动云端写入，改为按当前聊天手动备份与恢复。
+                    </div>
+                  </div>
+                </div>
+                <div class="bme-config-row">
+                  <label for="bme-setting-cloud-storage-mode">存储模式</label>
+                  <select
+                    id="bme-setting-cloud-storage-mode"
+                    class="bme-config-input"
+                  >
+                    <option value="automatic">自动储存</option>
+                    <option value="manual">手动储存</option>
+                  </select>
+                </div>
+                <div class="bme-config-help" id="bme-cloud-storage-mode-help">
+                  自动储存会继续按当前镜像逻辑同步；手动储存只保留本地写入，需要你主动备份和恢复。
+                </div>
+                <div
+                  class="bme-config-help"
+                  id="bme-cloud-storage-mode-status"
+                  style="display: none; margin-top: 8px;"
+                ></div>
+                <div
+                  id="bme-cloud-backup-manual-actions"
+                  class="bme-config-actions"
+                  style="display: none; margin-top: 12px; flex-wrap: wrap;"
+                >
+                  <button
+                    class="bme-config-secondary-btn"
+                    id="bme-act-backup-to-cloud"
+                    type="button"
+                  >
+                    <i class="fa-solid fa-cloud-arrow-up"></i>
+                    <span>备份到云端</span>
+                  </button>
+                  <button
+                    class="bme-config-secondary-btn"
+                    id="bme-act-restore-from-cloud"
+                    type="button"
+                  >
+                    <i class="fa-solid fa-cloud-arrow-down"></i>
+                    <span>从云端获取备份</span>
+                  </button>
+                  <button
+                    class="bme-config-secondary-btn"
+                    id="bme-act-manage-server-backups"
+                    type="button"
+                  >
+                    <i class="fa-solid fa-box-archive"></i>
+                    <span>管理服务器备份</span>
+                  </button>
+                  <button
+                    class="bme-config-secondary-btn"
+                    id="bme-act-rollback-last-restore"
+                    type="button"
+                    disabled
+                  >
+                    <i class="fa-solid fa-rotate-left"></i>
+                    <span>回滚上次恢复</span>
+                  </button>
+                </div>
+              </div>
+
               <div class="bme-config-grid bme-config-grid-2" style="margin-top: 20px;">
                 <div class="bme-config-card">
                   <div class="bme-config-card-head">

ui/ui-actions-controller.js

@@ -1123,6 +1123,7 @@ export async function onDeleteCurrentIdbController(runtime) {
   }
 
   const dbName = runtime.buildBmeDbName(chatId);
+  const restoreSafetyDbName = runtime.buildRestoreSafetyDbName?.(chatId) || "";
   if (
     !runtime.confirm(
       `确定要删除当前聊天的本地缓存数据库？\n\n目标: ${dbName}\n操作不可撤销。`,
@@ -1139,6 +1140,14 @@ export async function onDeleteCurrentIdbController(runtime) {
       req.onerror = () => reject(req.error);
       req.onblocked = () => resolve();
     });
+    if (restoreSafetyDbName) {
+      await new Promise((resolve, reject) => {
+        const req = indexedDB.deleteDatabase(restoreSafetyDbName);
+        req.onsuccess = () => resolve();
+        req.onerror = () => reject(req.error);
+        req.onblocked = () => resolve();
+      });
+    }
     runtime.toastr.success(`已删除数据库 ${dbName}`);
   } catch (error) {
     runtime.toastr.error(`删除失败: ${error?.message || error}`);

ui/ui-status.js

@@ -61,6 +61,12 @@ export function createGraphPersistenceState() {
     lastSyncUploadedAt: 0,
     lastSyncDownloadedAt: 0,
     lastSyncedRevision: 0,
+    lastBackupUploadedAt: 0,
+    lastBackupRestoredAt: 0,
+    lastBackupRollbackAt: 0,
+    lastBackupFilename: "",
+    syncDirty: false,
+    syncDirtyReason: "",
     lastSyncError: "",
     dualWriteLastResult: null,
     updatedAt: new Date().toISOString(),