The client-facing MCP proxy could exit with "Transport closed" when its
connection to the shared daemon hit a socket 'error' with no listener
attached — common on WSL2 /mnt (DrvFs), where AF_UNIX is flaky. The global
fatal handler turned that uncaughtException into process.exit(1), which the
MCP client saw as a bare transport close even though the index was healthy.
proxy.ts now keeps an 'error' listener on the daemon socket for its whole
life (and skips a socket destroyed in the connect window), so a stray error
degrades to the existing in-process fallback instead of crashing. daemon.ts
releases the lockfile it acquired when it fails to bind, so the next launch
doesn't spin on a stale lock (the duplicate serve --mcp pileup).
No default behavior change for anyone; WSL /mnt users who still hit trouble
can set CODEGRAPH_NO_DAEMON=1 to skip the shared daemon entirely. Validated
on macOS (unit + live serve probe) and Linux (Docker, --init): 64/64 across
the daemon/socket/lifecycle suites, incl. real AF_UNIX.
Closes#974
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
