fix(deps): resolve packages from PyPI instead of Azure DevOps feed

The lockfile was resolving all packages from the Azure DevOps private
feed, which requires authentication. CI lacks Azure credentials, causing
lint failures (401 Unauthorized on mypy-extensions download).

Add explicit PyPI index as default in pyproject.toml and regenerate the
lockfile so all public packages resolve from PyPI. The Azure feed
remains available via the uv-wrapper for local development when private
packages are needed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: lawrence-u10d

pyproject.toml

@@ -45,6 +45,11 @@ constraint-dependencies = [
     "pdfminer-six==20260107",
 ]
 
+[[tool.uv.index]]
+name = "pypi"
+url = "https://pypi.org/simple"
+default = true
+
 [tool.pyright]
 pythonPlatform = "Linux"
 pythonVersion = "3.12"