test: add plugin info-shape handlers

[wangyb-A]

Summary

• add Python conformance handlers for existing plugin requirements 10-19 through 10-23
• emit canonical hook-info field shapes directly from each SDK hook's own info object
• register each handler in the plugin SAM template

Requirement mappings

• 10-19 → invocation start/end info shape
• 10-20 → operation start/end info shape
• 10-21 → attempt start/end info shape with real SDK retry behavior
• 10-22 → operation-change delta item info shape
• 10-23 → context subtype and children-replay info shape

Validation

• Ruff lint and format checks
• conformance package unit tests: 10 passed
• documented handler build assembly
• import smoke test for all five built handlers
• sam validate --lint for the plugin template
• Gate B substantive requirement review: PASS

The live AWS conformance validator was not run locally.

[github-actions]

Codex AI review

[P1] Exercise actual ReplayChildren mode

This wait replays a still-STARTED context, but info.is_replay_children is only true for a completed context checkpointed with ContextDetails.ReplayChildren, normally after a serialized result exceeds 256 KiB. Consequently every isReplayingChildren record here is false. Have a child context complete with a large result, then force a subsequent invocation with a wait after that context so the true state is emitted and tested.

[github-actions]

Codex AI review

One issue prevents requirement 10-23 from exercising the ReplayChildren state.

Reviewed commit 32e260f26bd18c0a23b86a5bb835e820838e6629. Workflow run