Python: Expose forwardedProps to agents and tools via session metadata (#5264)

* Expose forwarded_props to agents and tools via session metadata (#5239)

Include forwarded_props from AG-UI request input_data in session.metadata
(agent runner) and function_invocation_kwargs (workflow runner) so that
agents, tools, and workflow executors can access request-level metadata
such as invocation source flags from CopilotKit.

- Add forwarded_props to base_metadata in _agent_run.py when present
- Add 'forwarded_props' to AG_UI_INTERNAL_METADATA_KEYS to filter it
  from LLM-bound client metadata
- Extract forwarded_props in _workflow_run.py and pass via
  function_invocation_kwargs to workflow.run()
- Accept both snake_case and camelCase keys (forwarded_props/forwardedProps)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix(ag-ui): pass stream=True as literal to satisfy pyright overload resolution (#5239)

The previous fix passed stream=True via **kwargs dict, which prevented
pyright from resolving the Workflow.run() overload to the streaming
variant. Pass stream=True as an explicit keyword argument so pyright
can correctly infer the ResponseStream return type.

Also remove unused pytest import in test file.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: address PR review feedback for forwarded_props (#5239)

- Use key-presence checks instead of truthiness for forwarded_props so
  empty dict {} is forwarded correctly
- Gate function_invocation_kwargs on workflow.run() signature inspection
  to avoid TypeError for workflows without **kwargs
- Change _build_safe_metadata to drop (with warning) keys whose
  serialized values exceed 512 chars instead of truncating into invalid
  JSON
- Rewrite metadata tests to exercise _build_safe_metadata directly with
  JSON-decodability and truncation assertions
- Add workflow tests for empty dict forwarded_props, stream=True
  assertion, and signature-gated kwarg dropping

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* test: add stream=True assertions to CapturingWorkflow tests (#5239)

Guard against accidental removal of the explicit stream=True kwarg
in all forwarded_props CapturingWorkflow test cases.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review feedback for #5239: Python: Expose forwardedProps to agents and tools via session metadata

---------

Co-authored-by: Copilot <copilot@github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

python/packages/ag-ui/tests/ag_ui/test_run.py

@@ -63,12 +63,12 @@ class TestBuildSafeMetadata:
         result = _build_safe_metadata(metadata)
         assert result == metadata
 
-    def test_truncates_long_strings(self):
-        """Truncates strings over 512 chars."""
+    def test_drops_long_strings(self):
+        """Drops strings over 512 chars instead of truncating."""
         long_value = "x" * 1000
         metadata = {"key": long_value}
         result = _build_safe_metadata(metadata)
-        assert len(result["key"]) == 512
+        assert "key" not in result
 
     def test_serializes_non_strings(self):
         """Serializes non-string values to JSON."""
@@ -77,12 +77,12 @@ class TestBuildSafeMetadata:
         assert result["count"] == "42"
         assert result["items"] == "[1, 2, 3]"
 
-    def test_truncates_serialized_values(self):
-        """Truncates serialized values over 512 chars."""
+    def test_drops_oversized_serialized_values(self):
+        """Drops serialized values over 512 chars instead of truncating."""
         long_list = list(range(200))
         metadata = {"data": long_list}
         result = _build_safe_metadata(metadata)
-        assert len(result["data"]) == 512
+        assert "data" not in result
 
 
 class TestHasOnlyToolCalls: