chore: sync community files

[albert20260301]

Summary

• synchronize CODE_OF_CONDUCT.md with the shared Contributor Covenant template
• synchronize SECURITY.md with the shared security-reporting template

Impact

This is a documentation-only consistency change. It does not modify the SDK API, runtime behavior, packaging, or public release surface.

The same managed files are already aligned in altertable-lakehouse-ruby, altertable-lakehouse-go, and altertable-lakehouse-js; the broader sync audit is tracked separately for repositories with larger drift.

Validation

• git diff --check
• npx --yes rumdl check --disable MD013,MD034 CODE_OF_CONDUCT.md SECURITY.md
• npx --yes markdown-link-check CODE_OF_CONDUCT.md SECURITY.md (7/7 links valid)

The local runner does not include Poetry or the repository's Python dev dependencies, so poetry run ruff check . and poetry run pytest could not run locally. This documentation-only change will receive the repository's normal CI validation.

[albert20260301]

@fvaleye could you review this?

I picked you because this is the Python SDK and your stack covers Python; the touched files have no core-team ownership signal. CI is pending on the newly opened PR. The review focus is that the two shared community documents exactly match the managed templates and do not affect SDK behavior.

[albert20260301]

@fvaleye this documentation-only synchronization PR has remained green and review-gated for four days. Could you review it when you have a slot? It only aligns CODE_OF_CONDUCT.md and SECURITY.md with the shared templates.