fix(optional): convert Optional[T] returns to T | None syntax; regen type registry

docs/type_registry/src_openai_schemas.md

@@ -30,7 +30,7 @@ Auto-generated from source. 6 struct(s) defined in this module.
 ## `src\openai_schemas.py::OpenAICompatibleRequest`
 
 **Kind:** `dataclass`
-**Defined at:** line 120
+**Defined at:** line 97
 
 **Fields:**
 - `messages: list[ChatMessage]`

docs/type_registry/src_provider_state.md

@@ -5,7 +5,7 @@ Auto-generated from source. 1 struct(s) defined in this module.
 ## `src\provider_state.py::ProviderHistory`
 
 **Kind:** `dataclass`
-**Defined at:** line 26
+**Defined at:** line 27
 
 **Fields:**
 - `messages: list[HistoryMessage]`

src/ai_client.py

@@ -726,17 +726,16 @@ def _gemini_tool_declaration_result() -> Result[types.Tool]:
   return Result(data=None, errors=[ErrorInfo(kind=ErrorKind.NOT_FOUND, message="No tool declarations to build", source="ai_client._gemini_tool_declaration_result")])
  return Result(data=types.Tool(function_declarations=declarations))
 
-def _gemini_tool_declaration_result_legacy_compat() -> Optional[types.Tool]:
+def _gemini_tool_declaration_result_legacy_compat() -> types.Tool | None:
  """
   LEGACY: prefer _gemini_tool_declaration_result() (returns Result[types.Tool]).
-  This wrapper is retained for tests that call _gemini_tool_declaration() directly;
-  it returns Optional[types.Tool] for backward compat only.
+  This wrapper is retained for tests that call _gemini_tool_declaration() directly.
   [C: tests/test_tool_access_exclusion.py:test_gemini_tool_declaration_excludes_disabled]
  """
  r = _gemini_tool_declaration_result()
  return r.data if r.ok else None
 
-def _gemini_tool_declaration() -> Optional[types.Tool]:
+def _gemini_tool_declaration() -> types.Tool | None:
  """Backward-compat alias for _gemini_tool_declaration_result_legacy_compat."""
  return _gemini_tool_declaration_result_legacy_compat()
 
@@ -3120,12 +3119,12 @@ def _run_tier4_patch_callback_result(stderr: str, base_dir: str) -> Result[str]:
   )
 
 
-def run_tier4_patch_callback_legacy_compat(stderr: str, base_dir: str) -> Optional[str]:
+def run_tier4_patch_callback_legacy_compat(stderr: str, base_dir: str) -> str | None:
  """LEGACY: prefer _run_tier4_patch_callback_result() (returns Result[str])."""
  r = _run_tier4_patch_callback_result(stderr, base_dir)
  return r.data if r.ok and r.data else None
 
-def run_tier4_patch_callback(stderr: str, base_dir: str) -> Optional[str]:
+def run_tier4_patch_callback(stderr: str, base_dir: str) -> str | None:
  """Backward-compat alias for run_tier4_patch_callback_legacy_compat."""
  return run_tier4_patch_callback_legacy_compat(stderr, base_dir)