Diagnose stale daemon runtime drift

[shuxueshuxue]

Summary

• record a lightweight CLI source fingerprint when the local daemon starts
• report Daemon Runtime: restart needed from cel self status when a running daemon no longer matches the current CLI code
• make cel self start fail loudly with the same restart guidance instead of only saying the daemon is already running

Why

A real tmux mixed-provider YATU exposed a stale daemon process still serving older imports after code changed. Restarting the daemon fixed wake delivery immediately. The runtime should surface that condition directly instead of making terminal wake look broken.

Verification

• uv run pytest tests/test_cli_self.py::test_self_status_reports_daemon_restart_needed_on_runtime_drift tests/test_cli_self.py::test_self_start_points_at_restart_when_running_daemon_drifted -q
• uv run pytest tests/test_cli_self.py tests/test_daemon_ipc.py tests/test_daemon_wake.py tests/test_daemon_surfaces.py tests/test_provider_hooks.py -q
• uv run pytest -q
• uv run ruff check packages/mycel-cli/src/mycel_cli/daemon/runtime_identity.py packages/mycel-cli/src/mycel_cli/self_cli.py packages/mycel-cli/src/mycel_cli/group/_cli/spawn.py tests/test_cli_self.py
• uv run ruff format --check packages/mycel-cli/src/mycel_cli/daemon/runtime_identity.py packages/mycel-cli/src/mycel_cli/self_cli.py packages/mycel-cli/src/mycel_cli/group/_cli/spawn.py tests/test_cli_self.py
• isolated MYCEL_HOME smoke: uv run cel self start, uv run cel self status, uv run cel self stop