Replaces the FlatCompat shim (which loaded .eslintrc.cjs via @eslint/eslintrc
and emitted deprecation warnings) with a native ESLint 9 flat config. Adds
typescript-eslint meta-package as the flat-config entrypoint and pins
@eslint/js to v9 to satisfy the eslint@9 peer range. Rule set is preserved
verbatim from the Phase 1A-1 plan (Task 4).
Align engines.node with the .nvmrc 24.2.0 pin so npm/pnpm warn on
mismatched local toolchains, move packageManager to the current
pnpm 9.15.3 patch, and ignore pnpm's local store and debug log so
stray artefacts never get committed.
Vitest 2 pulled Vite 5 + esbuild 0.21 (GHSA-67mh-4wv8-2f99). Bumping
vitest/@vitest/ui to v3 and adding vite ^6 as a direct dev dep forces
peer resolution onto Vite 6 + esbuild 0.25, which also clears the Vite
path-traversal advisory (GHSA-4w7w-66w2-5vf9). pnpm audit is now clean.
gnezim