fix(lsp-daemon): terminate proxy on stdin close to prevent orphaned processes

[PaoloC68]

Summary

Fixes #5560 — lsp-daemon MCP proxy processes accumulate as orphans across sessions.

When the parent process (opencode) exits, the proxy's stdin closes but dangling daemon socket handles keep the Node event loop alive, leaving the proxy (and its language server children) running indefinitely. Over multiple sessions this accumulates orphaned processes consuming 1+ GB of RAM.

Changes

packages/lsp-daemon/src/proxy.ts:

• Listen for stdin close event and force process.exit(0) after a 500ms grace period (handles parent killed via SIGKILL)
• Catch ERR_STREAM_PREMATURE_CLOSE from the server loop instead of propagating it as unhandled (stdin destroyed mid-request)
• Force process.exit(0) after the server loop returns normally when running on real stdin

All three paths are guarded by isRealStdin (input === process.stdin) so test harnesses using synthetic streams are unaffected.

packages/lsp-daemon/test/proxy.test.ts:

• Added regression test: stdin destroyed mid-session → proxy resolves cleanly instead of hanging

Test Results

 Test Files  10 passed (10)
      Tests  48 passed (48)

Root Cause Analysis

The for await (const chunk of input) loop in readStdioJsonRpcMessages exits on EOF, but:

1. If a daemon request is in-flight when stdin closes, the loop may not exit promptly
2. Even after the loop exits, open daemon socket connections keep the event loop alive
3. destroy() on stdin throws ERR_STREAM_PREMATURE_CLOSE which was unhandled

---

Summary by cubic

Terminate the lsp-daemon MCP proxy when stdin closes to prevent orphaned processes and memory leaks. Also handle premature stream closes and exit after the server loop so dangling sockets can’t keep the process alive.

• Bug Fixes
  • Listen for stdin close and force-exit after a 500ms grace period (real stdin only).
  • Catch ERR_STREAM_PREMATURE_CLOSE from the server loop instead of propagating it.
  • Exit after the server loop returns when using real stdin.
  • Add regression test: destroying stdin mid-session resolves the proxy.

^{Written for commit 6d081a8. Summary will update on new commits.}

[MoerAI]

Thanks @PaoloC68. Your orphan-prevention fix for the lsp-daemon proxy reviews cleanly and pairs well with the idle-timeout change in #5461. I cannot merge it yet: the test (ubuntu-latest) check is red on dev itself due to a pre-existing failure in packages/shared-skills/provenance-gate.test.ts, unrelated to your change. Once dev is green again I will re-run and merge. Nothing needed from you.