fix: preserve consumer logging ownership and routing

[codeforester]

CLI setup and teardown now close only lifecycle-owned handlers. Consumer handlers, explicit levels, and parent logging configuration survive an invocation; unconfigured loggers keep duplicate-free terminal output. The public logger helper accepts an explicit propagation policy.

Fixes #387.

Branch maintenance

Refs #426. Targets the branch for #414. Retarget and refresh after that parent is squash-merged; preserve the ordered stack.

The branch was refreshed without rewriting history to include main at a576cc279739eae5e4cfc33ffab2a7fb56de24de. The documentation conflict preserves both logger-ownership and timestamp configuration guidance.

Current-head validation

At b48e4443a1e7bde586679e975f28ad9713a916b7: uv lock freshness and baseline, runtime, strict typing, style, and contracts passed locally with all declared extras. Runtime result: 611 passed, 1 warning, 262 subtests passed in 8.75s.

Hosted checks: 7/7 required checks passed; 0 checks pending; 0 unsuccessful checks at 2026-10-04T14:19:40.760978+00:00. See the PR Checks tab and #426 for subsequent results.

[codeforester]

Reviewed against #387's acceptance criteria. Handler ownership via _base_cli_owned is the right shape, and consumer handlers are no longer closed or detached. CI is green.

I found one verified behavioral regression, inline. There are also two acceptance criteria without a test:

• dictConfig() routing: the criterion says logging.config.dictConfig()-configured base_cli handlers continue to receive records. test_parent_consumer_configuration_is_preserved uses addHandler on the parent, not dictConfig. I checked dictConfig by hand and it does work, partly because dictConfig resets child propagate itself. A test would pin that behavior.
• #341 nested run_app: the criterion says the nested-run_app guarantee still holds. No new test asserts it. Please confirm the existing #341 tests cover the new ownership-filtered cleanup path in context.py.

[codeforester]

Re-verified at 3f58457: all review feedback addressed ✅. I re-ran the original repro against the stack tip: with a consumer handler on base_cli.demo and no level set, configure_logger(..., debug=True) now leaves the effective level at DEBUG, and DEBUG reaches both the Base stream and the persistent log. The consumer handler is preserved, and an explicit consumer WARNING level is kept. Minor and non-blocking: _CONFIGURE_LOGGER_LOCK covers only the handler remove/add, while the foreign_handlers/level/propagate inspection still runs before the lock. Moving the with up a few lines would make the reply's 'inspect/remove/add serialized' claim literally true. Full suite passes at the tip. The threads can be resolved.