Clarify release version policy

[ip332]

Summary

• clarify that normal Git checkouts use commit-count-derived development versions;
• document that release tags provide the numeric version for archive fallback metadata and packaged artifacts;
• retain numeric X.Y.Z package versions for -rc.N tags;
• make the release reconstruction check explicit about the tag-derived artifact invariant.

The previous documentation incorrectly implied that a development checkout's numeric version must equal the release tag's numeric version. This correction matches the established v0.1.30-rc.2 release behavior.

Validation

• Release artifact manifest tests: 5/5
• git diff --check: PASS

No production code or normal Git version resolver changes. No compatibility epoch or format changes. No RC3 notes or artifacts are included.