refactor: remove Python 3.9 compatibility code

- Remove TODO comments for Python 3.9 support removal
- Remove MCP test skip conditions (Python 3.11 is now minimum)
- Regenerate uv.lock for Python 3.11+

Author: ryoppippi

stackone_ai/feedback/tool.py

@@ -1,6 +1,5 @@
 """Feedback collection tool for StackOne."""
 
-# TODO: Remove when Python 3.9 support is dropped
 from __future__ import annotations
 
 import json

stackone_ai/toolset.py

@@ -1,4 +1,3 @@
-# TODO: Remove when Python 3.9 support is dropped
 from __future__ import annotations
 
 import asyncio

tests/test_feedback.py

@@ -1,6 +1,5 @@
 """Tests for feedback tool."""
 
-# TODO: Remove when Python 3.9 support is dropped
 from __future__ import annotations
 
 import json

tests/test_toolset_mcp.py

@@ -1,16 +1,10 @@
-from __future__ import annotations
-
-import sys
 from contextlib import asynccontextmanager
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
 from stackone_ai.toolset import StackOneToolSet, _fetch_mcp_tools, _McpToolDefinition
 
-# MCP module requires Python 3.10+
-SKIP_MCP_TESTS = sys.version_info < (3, 10)
-
 
 @pytest.fixture
 def mock_mcp_catalog(monkeypatch):
@@ -327,7 +321,6 @@ def fake_fetch(_: str, headers: dict[str, str]) -> list[_McpToolDefinition]:
             toolset.fetch_tools()
 
 
-@pytest.mark.skipif(SKIP_MCP_TESTS, reason="MCP module requires Python 3.10+")
 class TestFetchMcpToolsInternal:
     """Test _fetch_mcp_tools internal implementation."""