Webdav (#923)

* feat: WebDAV backup/restore

- Add WebDAV test/backup/restore commands and settings\n- Fix ja i18n missing keys; decode PROPFIND href as UTF-8\n- Stabilize Windows prompt auto-import tests via CC_SWITCH_TEST_HOME

* chore: format and minor cleanups

* fix: update build config

* feat(webdav): unify sync UX and hardening fixes

* fix(webdav): harden sync flow and stabilize sync UX/tests

* fix(webdav): add resource limits to skills.zip extraction

Prevent zip bomb / resource exhaustion by enforcing:
- MAX_EXTRACT_ENTRIES (10,000 files)
- MAX_EXTRACT_BYTES (512 MB cumulative)

* refactor(webdav): drop deviceId and display deviceName only

---------

Co-authored-by: small-lovely-cat <77799160+small-lovely-cat@users.noreply.github.com>
Co-authored-by: saladday <1203511142@qq.com>

src-tauri/src/database/backup.rs

@@ -16,10 +16,15 @@ use tempfile::NamedTempFile;
 const CC_SWITCH_SQL_EXPORT_HEADER: &str = "-- CC Switch SQLite 导出";
 
 impl Database {
+    /// 导出为 SQLite 兼容的 SQL 文本（内存字符串）
+    pub fn export_sql_string(&self) -> Result<String, AppError> {
+        let snapshot = self.snapshot_to_memory()?;
+        Self::dump_sql(&snapshot)
+    }
+
     /// 导出为 SQLite 兼容的 SQL 文本
     pub fn export_sql(&self, target_path: &Path) -> Result<(), AppError> {
-        let snapshot = self.snapshot_to_memory()?;
-        let dump = Self::dump_sql(&snapshot)?;
+        let dump = self.export_sql_string()?;
 
         if let Some(parent) = target_path.parent() {
             fs::create_dir_all(parent).map_err(|e| AppError::io(parent, e))?;
@@ -38,6 +43,12 @@ impl Database {
         }
 
         let sql_raw = fs::read_to_string(source_path).map_err(|e| AppError::io(source_path, e))?;
+        let sql_content = sql_raw.trim_start_matches('\u{feff}');
+        self.import_sql_string(sql_content)
+    }
+
+    /// 从 SQL 字符串导入，返回生成的备份 ID（若无备份则为空字符串）
+    pub fn import_sql_string(&self, sql_raw: &str) -> Result<String, AppError> {
         let sql_content = sql_raw.trim_start_matches('\u{feff}');
         Self::validate_cc_switch_sql_export(sql_content)?;