emrg: offload remaining sync git probes from event loop (rant 2026-08-19T01:05:47)

[argszero]

Summary

Systematic audit per host rant 2026-08-19T01:05:47: no blocking calls in the asyncio event loop. The scheduler clone blocking (fixed in #858) was one instance; this PR closes the remaining sync git probes that run in async serving contexts.

Audit findings (this PR's scope)

Site	Context	Fix
daemon.pyprojects_list handler	On the event loop while serving websockets; ran _detect_git_remote (sync git remote get-url subprocess, 5s timeout) per project sequentially	await asyncio.to_thread(_detect_git_remote, ...) gathered in parallel
scheduler.pyapply_tasks (hot reload)	On the event loop while serving; TaskHandler.__init__ runs _detect_git_remote (git subprocess) + resolve_git_gh (file IO + cache write)	New _start_handler_async → asyncio.to_thread(self._build_handler, cfg); create_task still on the loop
scheduler.py boot path	_start_handler_for at daemon boot — no websocket clients connected yet	Kept sync (documented)

What was already compliant (verified, unchanged)

• emrg/tools/ — bash tool already asyncio.create_subprocess_shell; no other blocking calls (grep/glob/read/write/edit are file IO on the loop, sub-ms)
• emrg/connect.py — is_server_running_sync / socket.create_connection only called from client sync context and the daemon's pre-serve admission gate
• emrg/server/scheduler.py workspace self-heal git calls — already offloaded via asyncio.to_thread (emrg: scheduler workspace-heal async offload + clone backoff (rant 2026-08-19T00:54:32) #858)
• emrg/client/ — TUI process manager is a sync main loop, not an asyncio websocket server

Verification

• New tests (pure static-source assertions + existing mock-based apply_tasks tests run directly):
  • test_hot_reload_offloads_handler_construction_to_thread — apply_tasks awaits _start_handler_async; construction via asyncio.to_thread; boot path stays sync
  • test_daemon_projects_list_offloads_git_probe_to_thread — daemon source uses asyncio.to_thread(_detect_git_remote, ...) gathered
  • test_apply_tasks_hot_reload / test_apply_tasks_update_restart / test_apply_tasks_idempotent — still pass (behavior preserved)
• Import + CLI checks pass. Agent.md count 961 → 963 (2 new test functions).
• Full CI (ubuntu + windows, actionlint + doc-count guard) validates.

[argszero]

✅ LGTM — cycle 790 (Committer). CI test + test-windows both PASS on head 56feb3e (doc-count guard validated 963). Offloads verified: daemon projects_list gather+to_thread, scheduler _start_handler_async; boot path intentionally stays sync (pre-serve).

[argszero]

✅ LGTM — cycle 791 (Committer). Independent re-verify: head unchanged (56feb3e), CI test + test-windows PASS. Diff re-inspected — daemon projects_list to_thread+gather, scheduler _start_handler_async offload; boot path stays sync pre-serve. 2/3.

[argszero]

✅ LGTM — cycle 792 (Committer). 3rd consecutive approval. Head unchanged (56feb3e), CI green, MERGEABLE. Merging.