Add TypeScript types and a typed dataset entry point

[MrAlfak]

Goal

Make the generated HTTP status dataset easier to consume safely from TypeScript/JavaScript projects.

Proposed scope

• Define a TypeScript type/interface for standard and vendor entries.
• Export lifecycle/provider/source metadata with useful literal unions where practical.
• Add a small typed entry point without changing the source-of-truth data workflow.
• Document a minimal TypeScript usage example.

Acceptance criteria

• Types represent the v2 data model, including provider collisions and lifecycle states.
• Existing JSON consumers remain compatible.
• npm run lint, npm run build, and existing tests pass.
• README or docs include a short typed usage example.