Fix: VercelAIAdapter now accepts providerExecuted / title on dynamic-tool message parts

[he-yufeng]

Summary

• accept title and providerExecuted on dynamic-tool request parts
• keep parity with Vercel AI SDK dynamic tool parent fields
• add coverage across all dynamic-tool states

Fixes #5359.

To verify

• uv run pytest tests/test_vercel_ai.py -q -k "dynamic_tool_parent_fields" --basetemp .tmp/pytest-fast
• uv run pytest tests/test_vercel_ai.py -q --basetemp .tmp/pytest
• uv run python -m py_compile pydantic_ai_slim\pydantic_ai\ui\vercel_ai\request_types.py tests\test_vercel_ai.py
• uv run ruff format --check pydantic_ai_slim\pydantic_ai\ui\vercel_ai\request_types.py tests\test_vercel_ai.py
• uv run ruff check pydantic_ai_slim\pydantic_ai\ui\vercel_ai\request_types.py tests\test_vercel_ai.py
• uv run pyright pydantic_ai_slim\pydantic_ai\ui\vercel_ai\request_types.py tests\test_vercel_ai.py

[dsfaccini]

David's AICA here: I updated this branch with the follow-up fixes we discussed.

What changed beyond the original parse fix:

• Rebased/merged the branch onto current main so it is testing against the latest Vercel adapter code.
• Added title to static tool-* request parts too, since the AI SDK parent ToolUIPart includes it, not only DynamicToolUIPart.
• Preserved the semantics of providerExecuted on dynamic-tool parts when loading UI messages: dynamic provider-executed tool parts now become NativeToolCallPart / NativeToolReturnPart, matching pyai native/provider-executed tool history rather than being treated as ordinary function tools.
• Consolidated the request validation coverage so the same test covers static and dynamic tool parent fields across all tool states.
• Added adapter coverage for dynamic provider-executed output-available, output-error, and output-denied parts.

Verification run locally:

• uv run pytest tests/test_vercel_ai.py -q -k 'tool_parent_fields or provider_executed_dynamic_tool' --basetemp .tmp/pytest-pr5474-user

Result: 15 passed.

[DouweM]

@he-yufeng Thank you! Keep up the good work at Moonshot :)