docs: add project manifest

[shtse8]

Summary

• add PROJECT.md with repo goal, lifecycle, boundary, public surfaces, and delivery notes
• add .doctrine/project.json for central doctrine audit
• add AGENTS.md pointer to repo-local manifest and SylphxAI/doctrine

Validation

• python3 -m json.tool .doctrine/project.json
• python3 -m json.tool package.json
• Ruby YAML parse for workflows
• git diff --check
• doctrine project-control-plane-audit.py --repo SylphxAI/cat --ref codex/project-manifest-cat --fail-on-drift --json => PRESENT

Notes

• Documentation-only; no package code, docs site, CI, release, or package metadata changed.
• Manifest records benchmark-claim freshness and package release recovery as adoption gaps.

[shtse8]

Blocked by existing repository Biome check debt, not by the project manifest content.\n\nEvidence:\n- Latest run after formatting .doctrine/project.json: https://github.com/SylphxAI/cat/actions/runs/27913917017\n- New failure no longer reports .doctrine/project.json. Remaining diagnostics are existing repo files: examples/otlp-example.ts, examples/pure-refactor.ts, docs/.vitepress/config.ts, package.json files, packages/cat-tracing/src/index.ts, sylphx.json, turbo.json, and vercel.json.\n- The run reports: Found 51 errors.\n\nFollow-up issue: https://github.com/SylphxAI/cat/issues/9\n\nLeaving this PR open and blocked; I am not broad-formatting unrelated product files inside the manifest rollout.

[shtse8]

Superseded by #13, which landed the current main-based GroundAtlas project-control gate, vendor-neutral project.manifest.json, CI dogfood assertions, and release OIDC permission. Closing this stale/conflicting manifest PR to avoid duplicate project-control sources.