Add env-var overrides inside `._root.open_root_actor()` so
devs/test-runs can swap the actor-spawn backend or crank
console verbosity *without* touching application code.
In `._root.open_root_actor()`,
- read `TRACTOR_LOGLEVEL` early, overriding any caller-passed
`loglevel` and stashing an `env_ll_report` to emit once the
console log is set up.
- pull the `loglevel` fallback (`or _default_loglevel`) and
`log.get_console_log()` init *up* so the env-var report
routes through tractor's own logger.
- read `TRACTOR_SPAWN_METHOD`, overriding any caller-passed
`start_method` and warn-logging when the env-var clobbers
an explicit caller value.
Wire the same vars through `tests/devx/conftest.py::spawn`,
- request the `loglevel` fixture, set both `TRACTOR_LOGLEVEL`
and `TRACTOR_SPAWN_METHOD` in `os.environ` before each
`pexpect.spawn()` (inherited by the example subproc).
- expand `supported_spawners` to include
`main_thread_forkserver` and `subint_forkserver` bc
example scripts no longer need per-script CLI plumbing.
- pop both vars in fixture teardown so a leaked value can't
re-route a later in-process tractor test's spawn-backend
or loglevel.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Gud Boi
208e7c0926