Dependency upgrades

Logging these for now, but no immediate action needed.

• Tailwind 4 (currently 3) https://endoflife.date/tailwind-css (will eliminate tailwind.config.js)
• Next 16 (currently 15) https://endoflife.date/nextjs
  • "next lint is deprecated and will be removed in Next.js 16." so need to run npx @next/codemod@canary next-lint-to-eslint-cli . and then migrate eslint config from package.json to eslint.config.mjs
  • Might need to opt-in to next build --webpack, since turbopack becomes the default.
    • next build --turbopack errors to move @import before @tailwind, but doing so causes Pseudo-elements like '::before' or '::after' can't be followed by selectors like 'Delim('.')'.
    • See also below.
• next-intl 4 (currently 3)
  • Note that using next build --turbopack on version 3 causes a (ignorable) deprecation warning
• Typescript 6 (currently 5) https://en.wikipedia.org/wiki/TypeScript#Release_history

For next-intl 4, need to change global.d.ts to:

declare module 'next-intl' {
  interface AppConfig {
    Messages: typeof import('../locales/en.json');
  }
}

Turbopack

Turbopack support depends on https://github.com/CivicDataLab/opub-mono/pull/403

Need to add to next.config.ts (and add "raw-loader" to both package.json and knip.jsonc):

  turbopack: {
    rules: {
      '*.csv': {
        loaders: ['raw-loader'],
        as: '*.js',
      },
    },
  },

And need to re-order @import as above, e.g. something like:

@layer reset, base, components, utilities, app;

@import url('opub-ui/dist/assets/styles.css') layer(base);
@import url('./tokens/_variables.css');
@import url('nprogress/nprogress.css') layer(app);

@tailwind base;
@tailwind components;
@tailwind utilities;

And need to configure this postcss plugin in package.json (and add to devDependencies):

"postcss-import": { "path": ["node_modules"] }

Review the dependency checklist and the affected package.json, next.config.ts, global.d.ts, and stylesheet imports first. The migration includes the listed Tailwind, Next, next-intl, and TypeScript upgrades, plus the stated ESLint and Turbopack configuration changes. Done means the upgrades and required configuration are applied without the documented build and migration issues.