Reader side of the stream socket protocol, for zm_rtsp_server and any
in-tree consumer: connects to PATH_SOCKS/stream_{id}.sock with 1s retry,
reads exact-size length-prefixed messages into one reused buffer (no
per-read allocation churn, no resync scanning - contrast the FIFO
reader's 4KB chunking and memmem hunting), validates headers and
dispatches HELLO/MEDIA/KEYFRAME/STATS/BYE through callbacks on the
reader thread. Reconnects automatically on EOF or protocol error; a
fresh HELLO arrives after every reconnect. An adopt-fd constructor
supports tests and single-shot uses.
Tests: 5 new Catch2 cases - end-to-end against a real StreamSocket
(HELLO fields, media payload integrity), BYE + reconnect across a
server restart, fragmented byte-stream delivery via socketpair,
malformed-header disconnect, unknown-message-type skip. Full suite:
103/103 pass via ctest.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
