[mustafa-arda]

This PR represents Part 6 (the final stage) of the frontend dependency overhaul (#224).

-Package Bumps: Upgrades react-markdown to v10.0.0 and remark-gfm to v4.0.0.

-JSX Typing: Removes the temporary jsx-shim.d.ts since v10 natively supports React 19 types.

-Component Refactor: Accommodates the v10 API changes by removing the deprecated className prop from and wrapping its instances in a div.md-prose across OutputPane.tsx and StudyOutput.tsx.

-Testing: Resolves a major Jest transpilation deadlock caused by the massive nested ESM tree in the new markdown packages by stubbing them in mocks. The test suite is fully green (299 passing tests).

[lucaosti]

Thanks for taking on #224, this is a lot of work. I reviewed the whole stack (#300 to #304) here, since #304 contains the others. Trial merge with master: npm ci, type-check, lint, the 299 Jest tests and next build all pass, but the app loses its styling.

Blocking

• Tailwind is no longer loaded (#303). globals.css drops the @tailwind directives without adding @import "tailwindcss" or a @theme block, and tailwind.config.js is deleted. The custom tokens (blue-dark, surface, err, warn, max-w-8xl, the font stacks) and darkMode: 'class' are gone too. The built CSS of #304 is 7.5 KB with no utility classes at all (no .flex, .bg-blue-dark, .font-mono). CI cannot catch this, so please attach a before/after screenshot of the study page. With v4, class-based dark mode needs @custom-variant dark (&:where(.dark, .dark *));.
• Jest 30 is missing (#302). Its only commit changes one line in api-client.test.ts. jest, jest-environment-jsdom and @types/jest stay at 29 in every branch.
• The auth guard covers fewer routes (#301). proxy.ts replaces the guard's matcher, which covered every path except static assets, with ['/dashboard/:path*', '/courses/:path*']. / and any new page are no longer protected. Re-export config from auth-guard.ts as middleware.ts did.
• #300 cannot be merged on its own. Its CI is red: react-markdown 7 has no JSX namespace with the React 19 types, and the shim only arrives in #301. Simplest is to merge the upgrade as one PR, or squash the stack.

Should fix

• --legacy-peer-deps in CI and the Dockerfile hides peer conflicts instead of resolving them. It is also applied to the QVAC job, which #224 does not touch. With react-markdown 10 in place it should no longer be needed.
• In api-client.test.ts the assertion goes from /\/api\/courses$/ to /courses$/, so it no longer checks the /api prefix. Please find out why the base URL changed rather than loosening the test.
• The coverage-ratchet comment in jest.config.js was deleted, which is unrelated to the upgrade. Please restore it.

Minor / follow-up

• In eslint.config.mjs, reportUnusedDisableDirectives: false and react-hooks/set-state-in-effect: off turn off the new checks. That is fine for now if we track it. @eslint/eslintrc is added but never used.
• react-markdown and remark-gfm are mocked in Jest, so no test renders Markdown any more. Please mention this in the PR.
• TypeScript 7, also listed in #224, is not done yet.
• Several files gain a trailing blank line, and tsconfig.json is re-indented, which adds noise to the diff.

[lucaosti]

Thanks for the follow-up work, this is in much better shape. I ran npm ci, type-check, lint, jest and next build locally and all pass. Tailwind is back: the built CSS has the utilities, the custom tokens and the class-based dark mode. Jest 30 is in, the legacy-peer-deps flags are gone, and with a running server every route now redirects to /login when logged out. The snapshot update looks right too: the aspect-ratio was already in CourseCard, and the newer jsdom now records it.

A few small things before we merge:

• globals.css: the Google Fonts @import url(...) now sits after @import "tailwindcss" and @theme, so the build drops it (it warns "@import rules must precede all rules") and JetBrains Mono no longer loads. Could you move it to the very first line, or use next/font?
• api-client.test.ts: the original /\/api\/courses$/ assertion passes locally, so please restore it.
• jest.config.js: the ratchet comment got mangled (32?33, ranches is). Please restore the arrows and the backticks.
• package.json: please re-add "postcss": "^8.5.26" to overrides (it came from the security fix for #144), and reformat it with 2-space indentation and a final newline. Same for tsconfig.json and the stray trailing blank lines.
• Next 16 warns that middleware.ts is deprecated. The cleaner fix for the build collision is to keep src/proxy.ts and delete middleware.ts. While you are there, keep a single matcher: the one in the file now differs from auth-guard.ts (it adds api, drops public/) and the one in auth-guard.ts is unused.

Fine as separate issues: re-enable reportUnusedDisableDirectives and set-state-in-effect, add one test that renders real Markdown, TypeScript 7, and a quick visual check of rounded-sm and outline-none, which changed in Tailwind v4.

Since #304 contains the whole stack, let's merge only this one and close #300 to #303. Nice work getting all of this together.