bump zat + websocket.zig: fix handshake panic on TCP split mid-CRLF
websocket client read() panics when TCP delivers \r at buffer boundary
without \n — line_start advances past pos, causing start > end slice.
under ReleaseFast this was the silent SIGSEGV every 30-90 min.
websocket.zig 9ac64da, zat v0.3.0-alpha.17.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>