[rollout] fix: restore lint and verifytypes on main

[JoyboyBrian]

What

• Reformat tests/unit/rollout/test_harbor_backend_v2.py so it satisfies ruff format --check.
• Annotate HarborBackendV2.native_agent_kwargs as dict[str, Any] | None.

Why

main is currently red. Its most recent Tests run fails on two independent checks, and every branch cut from it inherits both — including #294, whose two failures are entirely this, not anything that PR changed.

lint fails because tests/unit/rollout/test_harbor_backend_v2.py does not satisfy ruff format --check under the pinned ruff 0.16.0. Reproducible locally with the same version: git show main:tests/unit/rollout/test_harbor_backend_v2.py > /tmp/t.py && ruff format --check /tmp/t.py reports one file would be reformatted. The fix is the formatter's own output; no behavior changes.

typecheck-pyright fails on the --verifytypes step, which reports native_agent_kwargs as "missing type annotation and could be inferred differently by type checkers". The attribute is assigned a conditional expression, and pyright will not commit to a type other checkers are guaranteed to agree on. Annotating it explicitly restores a clean run and does not change the value.

Both fixes are also present in #291, which is part of a larger stack that is not merging yet. Pulling them out lets main go green now rather than waiting on that review.

How to Test

• uv run ruff check . && uv run ruff format --check .
• uv run pyright osmosis_ai/ — 0 errors.
• uv run --no-editable pyright --verifytypes osmosis_ai --ignoreexternal, filtered the way .github/workflows/tests.yml filters it (skipping the agent_adapter, convert_sample_to_trajectory, and harness_agent baselines), reports no remaining errors.
• uv run pytest — 2019 passed.

Checklist

• PR title follows [module] type: description format
• Appropriate labels added (e.g. enhancement, bug, breaking)
• ruff check . and ruff format --check . pass
• pyright osmosis_ai/ passes
• pytest passes (new tests added if applicable)
• Public API changes are documented
• No secrets or credentials included

---

Summary by cubic

Restore CI by fixing ruff formatting and pyright --verifytypes failures on main. Reformats tests/unit/rollout/test_harbor_backend_v2.py and annotates HarborBackendV2.native_agent_kwargs as dict[str, Any] | None, with no behavior changes.

^{Written for commit fa2dc94. Summary will update on new commits.}