Add uv.lock and bump mypy target to 3.12

Adds the uv lockfile generated from pyproject.toml and updates

tool.mypy.python_version to 3.12 so third-party stubs parse cleanly

while keeping runtime compatibility at Python 3.11.

pyproject.toml

@@ -41,7 +41,10 @@ asyncio_mode = "auto"
 pythonpath = ["src"]
 
 [tool.mypy]
-python_version = "3.11"
+# Checked against Python 3.12 (the project's venv interpreter) so that third-party
+# stubs using newer syntax (e.g. numpy >= 2.5) parse cleanly. The code itself
+# must stay compatible with the 3.11 minimum declared in `requires-python`.
+python_version = "3.12"
 strict = true
 warn_return_any = true
 warn_unused_ignores = true