refactor: migrate validation from zod to valibot and update package dependencies

- Removed zod schema definitions and replaced them with valibot equivalents in zod_schema.ts.
- Updated user registration, login, and profile validation schemas to use valibot's validation methods.
- Deleted bun.lockb file.
- Added valibot as a dependency and updated devDependencies in package.json.

Author: SunPodder