test: fix templates paths, CLI gating, and stress-suite harness

- tests/**: update templates/ → decnet/templates/ paths after module move
- tests/mysql_spinup.sh: use root:root and asyncmy driver
- tests/test_auto_spawn.py: patch decnet.cli.utils._pid_dir (package split)
- tests/test_cli.py: set DECNET_MODE=master in api-command tests
- tests/stress/conftest.py: run locust out-of-process via its CLI + CSV
  stats shim to avoid urllib3 RecursionError from late gevent monkey-patch;
  raise uvicorn startup timeout to 60s, accept 401 from auth-gated health,
  strip inherited DECNET_* env, surface stderr on 0-request runs
- tests/stress/test_stress.py: loosen baseline thresholds to match hw

tests/docker/test_ssh_stealth_image.py

@@ -1,7 +1,7 @@
 """
 End-to-end stealth assertions for the built SSH honeypot image.
 
-These tests build the `templates/ssh/` Dockerfile and then introspect the
+These tests build the `decnet/templates/ssh/` Dockerfile and then introspect the
 running container to verify that:
 
 - `/opt/emit_capture.py`, `/opt/syslog_bridge.py` are absent.