Add governance/docs, CODEOWNERS, CI and Trust Authority admin/listing + aggregation tests

[blocksifrdev]

Motivation

• Prepare the repository for public readiness by adding governance, onboarding, and operator documentation, explicit repo access controls, and CODEOWNERS for critical paths.
• Harden the reference Trust Authority with operational admin routes and in-repo tests to increase confidence before public release.

Description

• Add global CODEOWNERS and a GitHub Actions CI workflow /.github/workflows/ci.yml that builds and runs tests for the Trust Authority reference implementation.
• Expand and reorganize docs and onboarding materials including CONTRIBUTING.md, README.md updates and many new files under docs/ such as getting-started.md, operator-guide.md, integration-guide.md (expanded), public-readiness.md, repo-access-control.md, open-source-boundary.md, ecosystem-integrations.md, and roadmap.md.
• Simplify and replace the long-form language spec files (ttp-language, ttp-language.md) with a pragmatic TTP language/semantics document that aligns with implemented schema and runtime semantics.
• Enhance the Trust Authority reference implementation with admin listing and metrics support by adding GET /v1/admin/agents in src/routes.ts and corresponding store APIs listAgents and getAgentReceiptsAcrossDomains in src/store.ts.
• Add project tooling and tests for the Trust Authority: jest.config.cjs, updated package.json (dev deps and @noble/hashes runtime dep), tsconfig.json tweak, and an aggregation unit test src/aggregation.test.ts that exercises aggregateTrustScore semantics including windowing and issuer weight capping.

Testing

• Added and ran unit tests in the Trust Authority reference implementation via npm test which executes Jest with reference-implementations/trust-authority/src/aggregation.test.ts and the test suite completed successfully.
• The new CI job trust-authority is configured to run npm install, npm run build, and npm test on push and pull_request events.

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Codex Task