fix(clients): expose WaitConfig and accept region_name aliases

[jariy17]

AgentCoreRuntimeClient accepts wait_config but users cannot import WaitConfig from its public package, and passing the region_name keyword used by other SDK clients raises TypeError.

Export WaitConfig from runtime, evaluation, gateway, knowledge_base, and policy, so callers can import it alongside the clients that accept it. Add region_name aliases to AgentCoreRuntimeClient and BatchEvaluationRunner, preserving all existing positional arguments and region selection: explicit region, then region_name, then the existing session/default fallback. Includes batch-runner precedence/compatibility tests and usage documentation.

Related to #663 (WaitConfig imports and region naming). Batch insights remain a separate discussion.

Validation:

• Remaining runtime and batch-runner tests: 85 passed.
• All pre-commit checks and the Bandit security scan passed.
• Built wheel checked in a clean Python 3.12 environment with base dependencies only; all five public imports and real boto3 client region selection passed without service calls.
• Verified a clean merge with the span-helper changes in fix(evaluation): expose shared span helpers and evaluator level lookup #674 and exercised the combined evaluation/runtime changes.

The initial full run hit an intermittent failure in the unchanged payment retry test's global time.sleep mock. All seven payment retry tests passed in isolation, and the full rerun passed. An unchanged-main comparison separately hit a memory timeout test's global time.time mock exhaustion; these unrelated tests were not changed here.

[github-actions]

⚠️ Breaking Change Warning

Found 1 potential breaking change(s) in this PR:

�[1msrc/bedrock_agentcore/runtime/agent_core_runtime_client.py�[0m:90: AgentCoreRuntimeClient.region: �[33mAttribute value was changed�[39m: validate_region(region or session.region_name if session else None or 'us-west-2') -> validate_region(region or region_name or session.region_name if session else None or 'us-west-2')

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Note: This is an automated static analysis check. Some flagged changes may be intentional.
Please confirm each item is expected and, if so, add a migration note to CHANGELOG.md.

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[jariy17]

CI note: the red Compat (evaluation) check is pre-existing and unrelated to this change. I'll address it in a follow-up PR.

The compat job installs pytest plugins only, so v1.23.1's tests_integ/evaluation/test_third_party_adapters.py errors at setup with ModuleNotFoundError: No module named 'ragas' / 'deepeval' (16 collection errors). The same failure occurs on unrelated branches, and the job is continue-on-error: true, so the workflow run itself reports success.

Same follow-up will cover the intermittent test_zero_delay_skips_sleep failure seen on this branch's first run: ragas starts a daemon thread at import time that loops on time.sleep(1), and our tests patch sleep through a module's own time reference — which is the shared stdlib module — so that thread's wake-ups land on the mock and inflate its call count.