Upgraded three TypeScript rules from "warn" to "error":
- explicit-function-return-type: Functions must declare return types
- prefer-nullish-coalescing: Enforce ?? over || for null checks
- prefer-optional-chain: Enforce ?. over && chains
This tightens pre-commit enforcement to catch more issues mechanically
before code review, reducing agent iteration cycles.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>