fix(types): ensure TypeScript declarations are generated on package pack and continuous release

[Pcmhacker-piro]

Resolves #9190

Changes:

• Added "prepack": "npm run generate-types" to package.json so that declaration files (types/p5.d.ts and types/global.d.ts) are automatically generated whenever npm pack or npm publish is run (e.g. during local manual releases or packaging).
• Added npm run generate-types step before publishing in .github/workflows/continuous-release.yml so that automated pkg-pr-new snapshots always include type declaration files.
• Added explicit .js extension to relative import import P5 from './p5.js'; in utils/typescript.mjs so that types/global.d.ts is fully compliant with ESM resolution (--moduleResolution node16 and nodenext).

---

Proof & Verification:

Real Terminal Video Demo (asciinema recording)

Terminal Output Screenshot

---

PR Checklist

• npm run lint passes (0 errors)
• Inline reference is included / updated
• Unit tests are included / updated (npm run test:types passes with 0 errors)

[Pcmhacker-piro]

Hi @ksen0 @limzykenneth, could you please review this PR when you get a chance? It resolves #9190 by adding "prepack": "npm run generate-types" to ensure declaration files (types/p5.d.ts and types/global.d.ts) are always automatically generated and included during packaging/publishing, adding type generation to the continuous release workflow, and fixing the relative import in global.d.ts for ESM nodenext resolution. Real terminal recording demo and proof screenshot are attached. Thank you!