chore(deps-dev): bump babel to v8 (grouped)

[ErickXavier]

Summary

Grouped major upgrade of the Babel 8 toolchain. Bumps both devDependencies together:

• `@babel/core` 7.29.7 → 8.0.1
• `@babel/preset-env` 7.29.7 → 8.0.2

Why grouped

Dependabot opened these as two separate PRs, each of which does only half of a coupled major upgrade and therefore fails `npm ci` alone with an ERESOLVE peer conflict:

• chore(deps-dev): bump @babel/preset-env from 7.29.7 to 8.0.2 #65 bumps `@babel/preset-env` → 8.0.2 (needs `@babel/core@^8`)
• chore(deps-dev): bump @babel/core from 7.29.7 to 8.0.1 #66 bumps `@babel/core` → 8.0.1 (breaks `preset-env@7`'s peer range)

They must land together. This PR supersedes #65 and #66 (leaving them open for the maintainer to close).

Local verification

• `npm install` — resolves with no ERESOLVE error; `@babel/core@8.0.1` and `@babel/preset-env@8.0.2` both on 8.x and deduped. (The only `invalid` peer notes come from jest's transitive `babel-preset-current-node-syntax`, whose legacy `@babel/plugin-syntax-*` packages peer-require core ^7 — inert under Babel 8.)
• `npm run build` — exits 0, dist rebuilt (byte-identical; Babel only drives the jest transform, not the esbuild bundle).
• `npm test` — 20/20 suites pass, 498 passed, 5 skipped, 0 failed (503 total).
• `npm audit` — 1 pre-existing moderate vuln (transitive `js-yaml`), unrelated to this change.