emrg: stop_all dual-write log to fixed path ~/.emrg/logs (tee)

[argszero]

Fixes host rant 2026-08-18T11:20:54 (stop_all.py 日志双写 — 固定路径 + 保留 Inno {tmp} 重定向).

The Inno installer redirects stop_all stdout to a random temp dir ({tmp}\stop_all.log) that is deleted when the install ends or is cancelled — the previous DeleteFile-code-5 forensics could only be captured while the dialog was still open. This adds a persistent fixed-path copy.

Changes (emrg/_stop_all.py, pure stdlib)

• _Tee class: write()/flush() proxy to both original stdout and the log file; per-write flush = crash-safe (append-mode means everything printed so far is on disk even if the installer force-kills the process — no finally dependency)
• _open_stop_log(): creates ~/.emrg/logs (mkdir parents) and opens stop_all-YYYYMMDD-HHMMSS.log (local time; timestamp name isolates concurrent runs)
• stop_all(): on entry, sys.stdout = _Tee(sys.stdout, f) + prints emrg stop: log also written to <path> so both the Inno-side log and the operator see the fixed location. Every existing print() automatically lands in both.
• Inno side untouched (still redirects stdout to {tmp}\stop_all.log for the failure dialog); POSIX emrg stop also leaves the fixed-path copy (tee regression-verified).

Tests: +4 (test_stop_all.py) — 929 → 933; full suite 933 collected, GUI 257/257, import + CLI green.

[argszero]

✅ LGTM — cycle 702. CI test + test-windows PASS (32096334926). Verified locally: _Tee dual-write (orig + file, per-write flush), _open_stop_log timestamp pattern + logs-dir creation, stop_all prints 'log also written to' and POSIX output regression-checked (exit 0 clean). test_stop_all.py 71 passed, full suite 933, GUI 257/257, import + CLI green.

[argszero]

✅ LGTM — cycle 703 (2nd). Head 87cc63d unchanged from cycle 702, CI test + test-windows PASS (32096334926), MERGEABLE.

[argszero]

✅ LGTM — cycle 704 (3rd). Head 87cc63d unchanged, CI test + test-windows PASS, MERGEABLE. 3 consecutive ✅ from cycles 702/703/704 — merging.