feat(fs): delegate win --server file reading to CM (#13736)

- Route Windows server-to-client file reads through CM instead of the connection layer
- Add FS IPC commands (ReadFile, CancelRead, SendConfirmForRead, ReadAllFiles) and CM data messages
  (ReadJobInitResult, FileBlockFromCM, FileReadDone, FileReadError, FileDigestFromCM, AllFilesResult)
- Track pending read validations and read jobs to coordinate CM-driven file transfers and clean them up
  on completion, cancellation, and errors
- Enforce a configurable file-transfer-max-files limit for ReadAllFiles and add stronger file name/path
  validation on the CM side
- Improve Flutter file transfer UX and robustness:
  - Use explicit percent/percentText progress fields
  - Derive speed and cancel actions from the active job
  - Handle job errors via FileModel.handleJobError and complete pending recursive tasks on failure
  - Wrap recursive directory operations in try/catch and await sendRemoveEmptyDir when removing empty directories

Signed-off-by: fufesou <linlong1266@gmail.com>

flutter/lib/models/model.dart

@@ -363,7 +363,7 @@ class FfiModel with ChangeNotifier {
           parent.target?.fileModel.refreshAll();
         }
       } else if (name == 'job_error') {
-        parent.target?.fileModel.jobController.jobError(evt);
+        parent.target?.fileModel.handleJobError(evt);
       } else if (name == 'override_file_confirm') {
         parent.target?.fileModel.postOverrideFileConfirm(evt);
       } else if (name == 'load_last_job') {