chore: replace Biome with oxlint, oxfmt and Knip

[Thomasims]

Replaces Biome with the shared @antelopejs/tooling-configs presets: oxlint
(type-aware, with the vendored anti-slop rules), oxfmt for formatting and Knip
for dead-code detection. oxlint is pinned to 1.81.0 because the JS plugin API
is still alpha and has to match the version tooling-configs builds against.

tsconfig

Type-aware linting runs through tsgolint, which rejects options TypeScript 7
removed, so moduleResolution: "node" and baseUrl are gone and the
self-referential @antelopejs/interface-api-util path mapping the test suite
uses is now written relative (./src/index.ts), which is what the compiler
wants once baseUrl is absent.

module stays commonjs on purpose. Raising it to node16 would look like the
tidier fix and is a runtime break: tsc stops downlevelling dynamic imports and
emits native ESM ones, which bypass the CommonJS resolver detour the ajs
runtime installs.

pnpm build succeeds with no source change.

Code changes the linter forced

Only import ordering, applied by oxlint --fix
(perfectionist(sort-imports)) in src/rate-limit.ts and
src/tests/rate-limit.test.ts. Nothing was disabled, and no public export was
touched: this package is a versioned contract, so its surface is deliberately
unchanged.

pnpm lint exits 0.

Knip

The suites live in src/tests/ and src/antelope.test.ts is read by
ajs module test from package.json#antelopeJs.test; the preset only knows the
src/test/ spelling, so both are declared as entry points. Without that, Knip
reads the whole suite as dead code. ajs itself is ignored as a binary because
CI installs @antelopejs/core globally instead of adding the CLI to every
package.

Nothing was deleted. Knip reports no unused files, exports or dependencies.

Verification

pnpm build, pnpm lint, pnpm knip, pnpm format:check all exit 0.
pnpm test: 19 passing, identical to the baseline measured on an untouched
main worktree.

The oxfmt pass is a separate commit and is recorded in .git-blame-ignore-revs
so git blame stays readable. It also normalizes Markdown, YAML and the
package.json key order, which accounts for most of the diff.