feat: update default birthdate initialization in forms

- Refactored birthdate initialization in FieldValidatorForm and UserForm to use a constant DEFAULT_BIRTHDATE for consistency.

chore: update devDependencies in package.json

- Upgraded various devDependencies including @happy-dom/global-registrator, @railway-ts/pipelines, @types/bun, @typescript-eslint/eslint-plugin, eslint, eslint-plugin-react-hooks, prettier, react, react-dom, and valibot to their latest versions.

test: simplify useDebounce tests

- Removed unnecessary fake timers setup in useDebounce tests for cleaner test structure.

Author: sakobu