Admin local development now starts on webpack
This story changes the admin dev server path from implicit Turbopack to explicit webpack so Tailwind v4 arbitrary-value classes keep compiling during local HMR.
What changed
The dev script now runs next dev --webpack. The old Turbopack-only root pin was removed from next.config.ts, leaving the webpack path free of dead Turbopack assumptions.
pnpm dev now starts the Next.js 16 development server with webpack explicitly selected.
allowedDevOrigins, logging, security headers, external packages, and existing experimental settings stay unchanged.
No OpenAPI snapshot, generated client, runtime data path, i18n, or pramaan-app file changes are part of this story.
Why it matters
Admin operators rely on dense internal screens where small spacing and sizing utilities matter. If local HMR silently drops an arbitrary Tailwind class such as w-[...], a developer can review a broken state as if it were correct. Using webpack for local dev matches the already deliberate app-side mitigation for the Next 16 Turbopack plus Tailwind v4 hazard.
Verification contract
Required gates for this PR: pnpm lint, pnpm typecheck or the repo-equivalent pnpm exec tsc --noEmit, pnpm test, pnpm build, pnpm build-storybook, git diff --check, and a pnpm dev boot smoke showing webpack startup.
Per pramaan-docs ADR-124, this is a dev/build configuration-only change with no new executable runtime path, so it is instrumentation-exempt.