Prepare Python package metadata for Determa State 0.0.7

[fruwe]

Summary

• bump the authoritative Python package version to 0.0.7;
• update current release-status documentation;
• align the existing public-version assertion with the package metadata;
• preserve the immutable format-1 specification and conformance commit pins.

Closes #65.

Validation

• ruff check .
• mypy src/determa
• pytest -q (175 passed)
• pytest conformance -q (93 passed, using the documented immutable commits because a v0.0.7 conformance tag does not exist yet)
• python -m build
• source archive and wheel content inspection
• clean wheel installation and determa.state.__version__ == "0.0.7"
• git diff --check

Exclusions

• no engine behavior or conformance expectation changes;
• no format identifier changes;
• no workflow or Trusted Publishing changes;
• no tag, release, or publication.