chore: remove knip, husky and lint-staged

Drop the unused knip dead-code check and the husky+lint-staged pre-commit hook pipeline. All checks remain covered by the CI workflow (lint, typecheck, i18n, tests).

scripts/prepare-hooks.mjs

@@ -1,5 +0,0 @@
-// Production builds and CI do not need Git hooks or dev-only executables.
-if (process.env.NODE_ENV !== "production" && !process.env.CI) {
-	const { default: husky } = await import("husky");
-	husky();
-}