Implement the P2 upload_file tool to push a local file or directory from the
master to an online Windows host over the existing V2 file-transfer protocol.
The server drives FileBatchTransferWorkerV2 synchronously on the main
connection through a headless callback, reuses the list_files chain for the
overwrite pre-check, and is gated by McpFileTransfer=1 plus McpReadonly=0.
The client main connection never initialized the file-transfer module, so
g_status stayed 0 and RecvFileChunkV2 silently dropped every chunk, truncating
uploads to zero bytes. Add a once-per-process lazy InitFileUpload in the
COMMAND_SEND_FILE_V2 handler that mirrors the FileManager init; the destructor
deliberately does not Uninit so g_status remains 1 across reconnects.
Update the design doc to record the client-side change and correct the
upload_file description to state that sha256 is not returned (V2 has no
receiver-to-sender ACK; integrity is checked client-side and logged only).
Co-Authored-By: deepseek-v4-pro
download_file pulls a remote file or directory back to the controller over
the existing V2 file-transfer protocol. It reuses COMMAND_LIST_DRIVE to open
the file-manager sub-link, then sends CMD_DOWN_FILES_V2 so the Windows client
streams COMMAND_SEND_FILE_V2 chunks and a per-file COMMAND_FILE_COMPLETE_V2
SHA-256 checksum over its own authenticated sub-connection. The server routes
those two packet types into a new per-device FileTransferSession whenever a
download is pending, so the headless path never opens the GUI progress dialog;
the C2C and existing GUI branches are left untouched.
Files are written under a normalized local_dir, and every chunk filename is
resolved and verified to stay inside local_dir (directories included) to block
.. traversal; overwrite=false skips existing files and counts them as skipped.
One transfer per host (mutually exclusive with the one-shot pending registry),
a dedicated McpFileTransfer=0-by-default gate surfaced in the settings dialog,
and audit logging complete the change. upload_file remains future work.
Co-Authored-By: deepseek-v4-pro
