Improve Windows source-checkout CLI ergonomics

[dikotiledon]

Summary

• accept shell-friendly top-level aliases (--update, --cluster-only) by normalizing -- tokens before command dispatch
• add repo-local Windows launchers (graphify.cmd, graphify.ps1) so cloned checkouts can run python -m graphify reliably from CMD/PowerShell
• refresh shell-facing docs and watch output to mention both shell and assistant invocation forms
• add regression tests for alias normalization and launcher/docs presence

Why

Windows users running Graphify directly from a cloned repository currently hit two friction points:

1. graphify --update fails even though graphify update works.
2. There is no repo-local launcher that reliably selects Python across .venv, �env, py -3, and python.

This PR makes that workflow predictable without changing existing command behavior for other platforms.

Verification

• python -m pytest tests/test_cli.py tests/test_windows_launchers.py
• python -m pytest -q (437 passed)