Replace Prettier and ESLint with oxfmt and oxlint

[TheGreatAxios]

Summary

• oxfmt formats the repo and oxlint is the lint gate; Prettier and ESLint are gone
• vendor stays ignored; dummy CI job names prettier and eslint remain for protect-main
• empty-function and non-null-assertion debt is errors, not warnings

Verification

• bun run check passes
• bunx oxlint . and bunx oxfmt --check . pass

Fixes CL-7376

[linear-code]

CL-7376