chore: align repo scaffolding with the package standard

[TheGreatAxios]

Closes CL-9401

Summary

• LICENSE replaced with Interchange's LGPL-2.1 text (was the FSF text). The CLA Assistant workflow (cla.yml, signatures on a cla-signatures branch) added; CLA.md already matched the shared text, and CONTRIBUTING links it.
• package.json: dropped main/types (exports covers Node and Bun), corbits added to keywords, engines bun >=1.2.0 and node >=24, build clears dist first, test runs bun test src --pass-with-no-tests, test:e2e runs bun test e2e, added a check script; db:setup and test:coverage stay. Key order is oxfmt's sortPackageJson order.
• tsconfig.json and tsconfig.build.json use the shared templates. Dropping allowImportingTsExtensions meant the e2e/ imports of ../src/*.ts now use .js. scripts/db-setup.ts is no longer in the typecheck include. The embed-model-registry.ts comment that pointed at IMPLEMENTATION.md now carries the one-time ALTER TABLE inline.
• .gitignore replaced with the shared template.
• ci.yml is now the standard single job: checkout v5, Node 24, a pgvector/pgvector:pg17 service on port 5432, bun run check, bun run test:e2e, then packs the tarball and imports createMemory, createMemoryRoutes, loadMemoryConfig, mountWorkflowMemory and createMemoryHttpClient under Node.
• Deleted: the nine committed .corbits/review-round2-*.md files, PRODUCT.md, ARCHITECTURE.md, IMPLEMENTATION.md, and docs/DISTILLER.md (nothing in the code references it). References to the deleted docs in src/grant-requirements.ts, docs/FEED.md and docs/RETENTION.md are removed.
• Kept in docs/, because they describe shipped behavior and the code points at them: AUTHZ-DOCUMENT-ACCESS.md, TEMPORAL.md, RELEVANCY.md, RETENTION.md, FEED.md. Their planning content is removed: the Acceptance checklist in AUTHZ-DOCUMENT-ACCESS.md, the unimplemented "Phase 2 — push" design in FEED.md, and ticket IDs in headings.
• Kept compose.yml and .env.example: CONTRIBUTING uses them for the local pgvector Postgres, Ollama and TEI reranker, and e2e/rerank-client.test.ts pins against the .env.example defaults.
• CONTRIBUTING trimmed to the standard (Development, CLA line, e2e and compose setup, Migrations, Commit messages; the CLA and branch sections are gone). AGENTS.md reshaped to Purpose, Layout, Rules (the four invariants unchanged), Local development; the Commands and Docs sections that pointed at the deleted docs are gone. README badges removed.
• CONTRIBUTING gets a Releasing section: releases are manual, as in Interchange (npm version, push tags, gh release create --generate-notes, npm publish).
• CHANGELOG.md removed; GitHub Releases track changes. The README changelog link goes with it.

Commits

1. chore: use the Interchange LICENSE text and add the CLA
2. build: align package.json and tsconfig with the package standard
3. ci: run check and a Node pack smoke
4. docs: trim CONTRIBUTING and AGENTS.md, drop planning docs and reviews

Checks

bun run build, check (291 unit tests), test:e2e (67 tests, local pgvector Postgres) and the Node pack-and-import smoke pass locally.