v0.3.0 - real framework integrations, security hardening, CI/CD

Minor version bump (0.2.5 -> 0.3.0) bundling seven previously merged but unreleased pull requests.

Security

• CRITICAL: delegation chain auth bypass fix (PR #45). Parent tokens and capability attenuation are now strictly verified on every delegation verify. Any long-lived delegation tokens issued prior to this release should be reviewed and re-issued.
• SSRF hardening on agent discovery, DID resolution, credential fetch (PR #47).
• Timing-safe comparisons for signature and token equality checks (PR #47).
• Seven REST API router exception paths no longer leak internals to clients (PR #47).

Added

• Real LangChain integration using BaseCallbackHandler (PR #42).
• Real OpenAI Agents SDK integration via MCPServerStdio (PR #48).
• Real CrewAI integration via MCPServerAdapter (PR #51).

Fixed

• Article 43 Annex III conformity assessment differentiates categories that require a notified body versus permitted self-assessment (PR #46).
• EAS schema UID derivation now matches the exact on-chain EAS encoding (PR #50).
• Attested event decoding prefers web3.py ABI decoding with a hardened topic-signature fallback (PR #50).

Infrastructure

• GitHub Actions CI/CD: pytest matrix (py 3.10, 3.11, 3.12, 3.13), ruff, mypy, bandit, pip-audit, plus a PyPI publish workflow on release creation (PR #49).
• Default pytest addopts include -p no:logfire to work around an opentelemetry-sdk / logfire ABI mismatch pulled in transitively by CrewAI.

Release verification

• python -m pytest tests/ - 358 passed, 1 skipped
• twine check dist/* - wheel and sdist PASSED
• PyPI: https://pypi.org/project/attestix/0.3.0/
• MCP Registry: io.github.VibeTensor/attestix

Install: pip install --upgrade attestix