Python: Fix workflow tests pyright warnings

[TaoChenOSU]

Motivation and Context

Closes #777

Description

Fix warnings appear in workflow test files. Since workflow rely on typing, we are also enabling type checks for workflow tests.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
TOTAL	22222	2759	87%

report-only-changed-files is enabled. No files were changed during this commit :)

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
4717	247 💤	0 ❌	0 🔥	1m 18s ⏱️

[Copilot]

Pull request overview

This PR updates the Python workflow test suite to eliminate pyright/typing warnings and (intendedly) bring workflow tests under stricter type checking to better match the workflow system’s typing-heavy design.

Changes:

• Adjusts pyright configuration to include workflow tests and stop globally excluding **/tests/**.
• Tightens typing in workflow tests (e.g., AgentRunInputs, WorkflowEvent[Any], overloads for run(stream=...)).
• Adds targeted pyright: ignore[...] / type: ignore[...] annotations where tests intentionally touch private APIs or untyped constructs.

Reviewed changes

Copilot reviewed 25 out of 26 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
python/pyproject.toml	Updates pyright include/exclude settings to (intendedly) type-check workflow tests.
python/packages/core/tests/workflow/test_workflow_states.py	Adds explicit generic typing for filtered WorkflowEvent lists.
python/packages/core/tests/workflow/test_workflow_observability.py	Adds pyright ignores and stronger local variable typing for OTEL span tests.
python/packages/core/tests/workflow/test_workflow_kwargs.py	Adds overloads + AgentRunInputs typing for test agents; refines option dict typing.
python/packages/core/tests/workflow/test_workflow_context.py	Adds ignores for intentionally-invalid typing cases used in validation tests.
python/packages/core/tests/workflow/test_workflow_builder.py	Adds overloads and stream typing to DummyAgent; minor pyright ignores for private access.
python/packages/core/tests/workflow/test_workflow_agent.py	Adds overloads + missing session method typing for embedded test agents; narrows a union attr ignore.
python/packages/core/tests/workflow/test_workflow.py	Adds overloads and improves typing of state and filtered streamed outputs.
python/packages/core/tests/workflow/test_viz.py	Adds typing for fixtures/tmp_path and an import ignore for graphviz exception.
python/packages/core/tests/workflow/test_validation.py	Adds pyright ignores for intentionally-invalid executor classes; ignores private usage asserts.
python/packages/core/tests/workflow/test_typing_utils.py	Adds pyright ignores for tests that pass union-type expressions as values.
python/packages/core/tests/workflow/test_state.py	Adds pyright ignores for assertions against private state internals.
python/packages/core/tests/workflow/test_runner.py	Updates checkpointing context signatures/types and adds pyright ignores for private runner methods/fields.
python/packages/core/tests/workflow/test_request_info_mixin.py	Adds explicit Any annotations to satisfy strict type checking for decorator-driven tests.
python/packages/core/tests/workflow/test_function_executor_future.py	Adds pyright ignores for private executor internals used in assertions.
python/packages/core/tests/workflow/test_function_executor.py	Adds typing refinements and pyright ignores for private internals and unknown types in negative tests.
python/packages/core/tests/workflow/test_full_conversation.py	Adds overloads and updates context generics for agents/coordinators used in full-conversation tests.
python/packages/core/tests/workflow/test_executor_future.py	Adds pyright ignores and typing adjustments in future-annotation executor tests.
python/packages/core/tests/workflow/test_executor.py	Adds pyright ignores and formatting/typing tweaks around handler decorators and event filtering.
python/packages/core/tests/workflow/test_edge.py	Adds OTEL exporter typing and minor safety asserts for test helpers.
python/packages/core/tests/workflow/test_checkpoint_encode.py	Adds casts and pyright ignores for private constants used in encoding tests.
python/packages/core/tests/workflow/test_checkpoint.py	Improves typing of dataclass fields and adds targeted ignores for raw-serialization test inputs.
python/packages/core/tests/workflow/test_agent_utils.py	Refactors mock agent typing to match AgentRunInputs and streaming overload patterns.
python/packages/core/tests/workflow/test_agent_executor_tool_calls.py	Adds overloads + AgentRunInputs typing and tightens assertions on text content.
python/packages/core/tests/workflow/test_agent_executor.py	Adds overloads + AgentRunInputs typing, stream typing, and pyright ignores for private API usage.