codmap 0.0.3 — the first published release

First release on PyPI, as the distribution `codmap` (the command, the import and
the repository stay `codemap`; the bare name was taken). Ships everything that had
accumulated since 0.0.2: flat-layout support, source-visible references, the deep
tier as a union with the fast one, graph provenance (schema 0.12), test mapping,
hard-Python robustness, and M20 — CI, honest package metadata, and a measured
Python range.

Verified from PyPI into a clean venv, run outside any source tree.