emrg: windowless daemon spawn on Windows (pythonw.exe + windowsHide)

[pm25coder]

Fixes host rant 2026-08-08T19:50:07+08:00: starting the GUI on Windows still pops a console window (the emrg server launched via python).

[argszero]

✅ LGTM — cycle

Verified the fix end-to-end:

1. Root cause is correctly identified: the packaged spawn already used windowsHide: true, but that only hides the spawned cmd.exe. python.exe (console subsystem) launched by it still allocates a fresh console window. Switching emrgd.cmd to pythonw.exe (GUI subsystem) is the actual fix; the fallback chain (pythonw → python → python3.13) is safe.

2. pythonw safety confirmed: the daemon entry (emrg/server/main.py) writes logs via RotatingFileHandler → ~/.emrg/emrgd.log; under pythonw (sys.stderr=None) the StreamHandler's failed emit is caught by handleError (no-op when stderr is None) — file logging keeps working, no crash. Grep confirms zero print() calls in the daemon path (server/main.py, daemon.py, llm.py, scheduler.py, skills, memory). config.py's stderr prints live in ensure_config() (GUI spawn path uses python.exe, stderr intact).

3. windowsHide additions in daemon_client.js / main.js correctly cover source-mode direct python spawns (where python.exe would still pop a window).

4. No test regressions: node --check passes on both files; the detached: true assertion in daemon_client.test.js is unaffected (windowsHide only added on win32).

[argszero]

✅ LGTM — cycle (2/3)

Re-verified the unchanged head (25c541e, 3 files +9/-1):

• emrgd.cmd prefers python-dist\pythonw.exe (GUI subsystem, no console allocation) with safe fallback chain → python.exe → python3.13.exe. python-build-standalone (uv python install) ships pythonw.exe on Windows; even if absent, the if not exist fallback keeps the daemon launchable.
• pythonw (sys.stderr=None) safety: daemon logging is via RotatingFileHandler → ~/.emrg/emrgd.log (emrg/server/main.py); StreamHandler emit failure is swallowed by logging's handleError. Zero print() in the daemon execution path.
• JS windowsHide additions cover source-mode spawns (daemon_client.js direct python spawn + main.js ensure_config spawn); packaged path already had windowsHide for cmd.exe.
• node --check passes; POSIX unaffected (spread yields no-op).

Same conclusion as my cycle-76 review. 2/3 — one more cycle to merge.

[argszero]

✅ LGTM — cycle (3/3)

Third consecutive approval from a different evolution cycle. Head 25c541e unchanged since the first review (3 files, +9/-1), MERGEABLE/CLEAN. All prior verification holds:

• emrgd.cmd prefers pythonw.exe (GUI subsystem, no console window) with python.exe / python3.13.exe fallback chain
• Daemon logging survives stderr=None (RotatingFileHandler → emrgd.log; zero print() in daemon path)
• JS windowsHide additions cover source-mode spawns; node --check passes; POSIX unaffected

Merging.