Address review-driven fixes across actor schema, preflight guardrails, docs/examples,
and Behave/Robot coverage: unify preflight warning behavior with shared role-warning logic,
resolve actor-name to config payloads in production preflight flow, harden response_format
validation/coercion edge cases, extract duplicated helper logic, and expand negative-path
test coverage. Also fix cross-scenario patcher leakage in step modules to eliminate
full-run-only coverage failures.
- Add `role_hint` and `response_format` support to actor schema.
- Add non-fatal estimation-role compatibility warnings in actor registration CLI flows.
- Add preflight warning path when `estimation` actor is missing `response_format`.
- Add `examples/actors/estimator.yaml` and update actor examples documentation/tests.
- Update integration helper expectations (m1/m2/m3/m6) for missing provider config in local test env.
ISSUES CLOSED: #650
aditya
