tmux-windows: äldre versioner att ladda ner

SSH Session Survival

The tmux server now survives SSH disconnects. Previously, closing an SSH
connection would terminate the tmux server and all attached sessions,
because Windows OpenSSH uses job objects to kill all child processes when
a session ends.

Changes:
- Server launch uses CREATE_BREAKAWAY_FROM_JOB to detach from the SSH
job object, the Windows equivalent of Unix setsid()
- Falls back to previous behavior if the job does not allow breakaway
- Sessions started over SSH can be reattached from the local console
or a new SSH connection

Single-File Static Distribution

tmux-windows is now a single statically-linked executable with no DLL
dependencies. Previously the release included event_core.dll (libevent);
this is now compiled directly into tmux.exe.

Changes:
- Switched vcpkg triplet from x64-windows to x64-windows-static so
libevent is linked into tmux.exe at build time
- Release ZIP contains only tmux.exe — no DLLs, no README.txt
- Simpler deployment: just drop tmux.exe into your PATH

TTY Race Condition Fix & Security Hardening

Fixes the startup reliability issue where tmux new would intermittently fail
with "open terminal failed: not a terminal" or display a blank screen. Also
hardens the named pipe IPC against command injection and enables truecolor
by default.

Startup Race Condition Fix:
- Client: move TTY channel connection before identify messages, giving the
server maximum time to accept it
- Server: defer command processing with a blocking cmdq callback when the
TTY channel has not arrived yet; 2-second safety timeout
- Late init: preserve terminal dimensions across tty_init() memset, then
force recalculate_sizes() and full redraw

Security Hardening:
- Sanitize IPC label names to prevent arbitrary named pipe paths via
crafted -L arguments
- Cap pending TTY connection queue at 16 entries with 30-second expiry

Truecolor Support:
- 24-bit color now enabled by default on Windows