TSM-90: switch to source-generated declarations

[Justin Hammond (Justintime50)]

Summary

• Switch declaration generation from manually maintained root types/ files to source-generated declarations.
• Publish declarations from dist/types and update package metadata accordingly.
• Remove tracked root types/ artifacts and obsolete types/demo CI dependency.
• Keep runtime outputs and package import/require behavior unchanged.

Validation

• npm run formatCheck
• npm run lint
• npm run typescript
• npm run build
• npm run scan
• clienv npm test