初始提交：terminalX 可运行态（M0/M1/M1.5 已真机验证）

- M0: libghostty SSH 终端（渲染/输入/连接）+ 白屏修复(OutputGate) + 会话状态机/自动重连
- M1: tsnet 用户态组网 + SSH-over-tsnet(fd 桥)，shell 级真机验证；R5(Go+gvisor+C+++Swift 同进程) retire
- M1.5: tmux -CC 原生 tab（MVP）
- 结构: packages/(TXCore·TXTransport), apps/TerminalX, vendor/(libghostty-spm/libssh2/mbedtls/tsnet-bridge), artifacts/
- 文档: CLAUDE.md + docs/HANDOFF.md（新会话入口）
- 环境: 认证代理→依赖 vendor 本地化；Go 在 ~/.local/go；仅模拟器/未签名
- 待续: M2 mosh, tmux 多 pane, M4 安全(host key/SE)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

vendor/libssh2/docs/libssh2_sftp_write.3

@@ -0,0 +1,73 @@
+.\" Copyright (C) The libssh2 project and its contributors.
+.\" SPDX-License-Identifier: BSD-3-Clause
+.TH libssh2_sftp_write 3 "1 Jun 2007" "libssh2 0.15" "libssh2"
+.SH NAME
+libssh2_sftp_write - write SFTP data
+.SH SYNOPSIS
+.nf
+#include <libssh2.h>
+#include <libssh2_sftp.h>
+
+ssize_t
+libssh2_sftp_write(LIBSSH2_SFTP_HANDLE *handle,
+                   const char *buffer,
+                   size_t count);
+.fi
+.SH DESCRIPTION
+\fBlibssh2_sftp_write(3)\fP writes a block of data to the SFTP server. This
+method is modeled after the POSIX write() function and uses the same calling
+semantics.
+
+\fIhandle\fP - SFTP file handle as returned by \fIlibssh2_sftp_open_ex(3)\fP.
+
+\fIbuffer\fP - points to the data to send off.
+
+\fIcount\fP - Number of bytes from 'buffer' to write. Note that it may not be
+possible to write all bytes as requested.
+
+\fIlibssh2_sftp_handle(3)\fP will use as much as possible of the buffer and
+put it into a single SFTP protocol packet. This means that to get maximum
+performance when sending larger files, you should try to always pass in at
+least 32K of data to this function.
+.SH WRITE AHEAD
+Starting in libssh2 version 1.2.8, the default behavior of libssh2 is to
+create several smaller outgoing packets for all data you pass to this function
+and it will return a positive number as soon as the first packet is
+acknowledged from the server.
+
+This has the effect that sometimes more data has been sent off but is not acked
+yet when this function returns, and when this function is subsequently called
+again to write more data, libssh2 will immediately figure out that the data is
+already received remotely.
+
+In most normal situation this should not cause any problems, but it should be
+noted that if you have once called libssh2_sftp_write() with data and it returns
+short, you MUST still assume that the rest of the data might have been cached so
+you need to make sure you do not alter that data and think that the version you
+have in your next function invoke will be detected or used.
+
+The reason for this funny behavior is that SFTP can only send 32K data in each
+packet and it gets all packets acked individually. This means we cannot use a
+simple serial approach if we want to reach high performance even on high
+latency connections. And we want that.
+.SH RETURN VALUE
+Actual number of bytes written or negative on failure.
+
+If used in non-blocking mode, it returns LIBSSH2_ERROR_EAGAIN when it would
+otherwise block. While LIBSSH2_ERROR_EAGAIN is a negative number, it is not
+really a failure per se.
+
+If this function returns 0 (zero) it should not be considered an error, but
+that there was no error but yet no payload data got sent to the other end.
+.SH ERRORS
+\fILIBSSH2_ERROR_ALLOC\fP - An internal memory allocation call failed.
+
+\fILIBSSH2_ERROR_SOCKET_SEND\fP - Unable to send data on socket.
+
+\fILIBSSH2_ERROR_SOCKET_TIMEOUT\fP -
+
+\fILIBSSH2_ERROR_SFTP_PROTOCOL\fP - An invalid SFTP protocol response was
+received on the socket, or an SFTP operation caused an errorcode to
+be returned by the server.
+.SH SEE ALSO
+.BR libssh2_sftp_open_ex(3)