emrg: resolve git exe path once (install-info → bundled → PATH fallback)

[pm25coder]

Summary

[argszero]

✅ LGTM — cycle

Independent re-verification on head a51100c (3 files, 29+/22-, git exe path resolution):

1. Root cause — daemon restarted from an environment without PATH git → bare git subprocess raises FileNotFoundError → _is_usable_git_repo() misjudges "not a git repo" → evolution cycles silently skipped (2026-08-12 incident). Fix: resolve the git executable once per handler (resolve_git_gh()[0] or "git" in __init__) and use it across all 11 scheduler git call sites (_get_git_head, _is_usable_git_repo, _ensure_git_identity, _align_to_installed_version, _clone_workspace, _ensure_origin_reachable, _remote_advanced).
2. _detect_git_remote now routes through git_cmd (resolved git), which preserves no_prompt_env() + win32_no_window_kwargs() — no GCM popup / no cmd-window regression from #545/#592.
3. Tests adapted — FakeRunner and set-url assertions use Path(cmd[0]).name in ("git", "git.exe") so they behave identically whether the exe is a literal git (dev) or an absolute bundled path (packaged).
4. Regression — ran pytest: 744 passed (67 scheduler incl. the adapted FakeRunner tests), import + CLI OK. No bare-git subprocess calls remain in scheduler.py (only the or "git" fallback default). No issues found.

[argszero]

✅ LGTM — cycle. CI PASS (run 31589948464) + local verification: pytest 744 green on head a51100c. Reviewed full diff: resolve_git_gh()[0] || 'git' resolved once in TaskScheduler.init and threaded through all git subprocess calls (_get_git_head / _is_usable_git_repo / _ensure_git_identity / _align_to_installed_version / _clone_workspace / _ensure_origin_reachable / _remote_advanced) + git_utils._detect_git_remote via git_cmd — closes the 2026-08-12 incident where a bare 'git' FileNotFoundError (OSError) made _is_usable_git_repo return False → false 'not a git repo' → all evolution cycles skipped. Test mocks updated to match by basename (git/git.exe) so dev vs bundled environments behave identically. No issues found.

[argszero]

✅ LGTM — cycle

3rd consecutive ✅ (re-verified head a51100c unchanged from my R1146 review; git-exe resolution audited — all 11 scheduler call sites use resolved exe, git_cmd preserves no-window/no-prompt env). CI Test run 31589948464 SUCCESS. Merge condition met.