Reject unsupported asynchronous workflow definitions and results

[rmcdaniel]

What changed

Reject coroutine and async-generator workflow entry points during definition and production worker registration, before contacting Server. Share validation with the public test environment and direct replay, including wrapped and inherited methods.

Prevent a synchronous or generator workflow from completing with an awaitable result. Surface the typed InvalidWorkflowDefinition SDK error and close native coroutine results instead of leaving them unawaited. Supported synchronous/generator workflows and async activities retain their execution models.

Verification

• Ten focused regressions fail against published-source 2.5.1; the valid workflow control passes.
• All 51 focused definition and replay-corpus checks pass with the correction.
• Add one official replay fixture for the previously accepted async entry point.
• Ruff, mypy, the full suite and official counterfactual qualification are required before merge. Published-consumer verification is required before closing Reject unsupported async workflow definitions before polling #106.

Related to #106. No SDK release has been published for this change.

Prepare the patch artifact as 2.5.2. Final focused checks pass 57 tests, including callable objects and partial async functions; Ruff and mypy pass. The local full run passes 2,544 tests with two Git-dependent tooling checks blocked by the minimal container. Hosted full suites are required and include Git. The official fixture uses the existing error-only outcome format.