chore(deps-dev): bump @babel/core and @babel/preset-env to 8

[aharoitx]

Bumps @babel/core (7.29.7 → 8.0.1) and @babel/preset-env (7.29.7 → 8.0.2) together.

Dependabot opened these as separate PRs (#344, #343), which fail CI because
@babel/preset-env@8 requires @babel/core@^8
bumping only one half breaks the peer.
Combining both in one change resolves it.

Verified locally: npm ci, build, format:ci, lint, unit (54/54), and audit all pass.

Note: ts-jest emits ERESOLVE peer warnings because it declares @babel/core as an
optional peer (it doesn't use Babel here). These are non-blocking — all checks pass.

Supersedes #344 and #343. Tracks #310.

[aharoitx]

Closing — bumping @babel/core to 8 fails npm ci in CI because ts-jest@29.4.11
declares an optional peer "@babel/core >=7.0.0-beta.0 <8", and no ts-jest release
supports @babel/core 8 yet (latest is 29.4.11; even the next tag caps at <8).
Babel here is dev-only test tooling, so we'll hold at 7 and revisit when ts-jest
ships Babel 8 support.