chore: modernize Node and action tooling

[oflynned]

Summary

• target Node 24 across local, Docker, and CI environments
• replace the unmaintained actions-toolkit wrapper with official @actions packages
• update the TypeScript, Jest, ESLint, packaging, and dependency stack
• make the Docker build portable and remove Codecov

Verification

• npm run lint
• npm run typecheck
• npm test -- --runInBand (51 passing)
• npm run build
• npm run package
• npm run audit:prod (0 production vulnerabilities)
• docker build -t android-version-bump:e2e-baseline .