build: upgrade to vite v8 (rolldown) and vitest v4

[kissu]

I saw some ticket created here by @stvncode about a Vite 8 bump and decided to help a little (normal prio + tiny size). 🤗

Changelog

• vite ^7.3.2 → ^8.0.16
• vitest ^3.2.4 → ^4.1.8
• @vitest/coverage-v8 → ^4.1.8
• @vitest/ui → ^4.1.8

Why

Vite 8 ships Rolldown (Rust bundler) as the default, which roughly halves the
production build phase (see table). The previous blocker — vite-plugin-pwa Vite-8
support — is already resolved (1.3.0, the installed version).

Vitest 3 → 4 is required, not optional: vitest 3 peer-caps at vite ^7, while
vitest 4 supports ^8. @vitest/coverage-v8 and @vitest/ui move with it to stay in
lockstep. All seven vite-plugin-* / @vitejs plugins already declare Vite 8 support
at their installed versions, so no plugin bumps were needed.

I used taze to bump the dependencies and checked manually on each projects to ensure the state + breaking changes, everything is clear. 👍🏻
Moreover, vitest is going on its v5 soon hence the v4 was IMO safe given the small configuration + due.

Before / after (production build, Node 22.18.0)

Metric	Vite 7.3.2	Vite 8.0.16
Vite build phase (✓ built in)	20.16s	10.05s (−50%)
yarn build total (incl. vue-tsc)	31.81s	20.55s (−35%)
Bundle (du -sh)	14M	14M
Largest chunk	3,408 kB	3,215 kB
PWA precache	172 / 7,177 KiB	174 / 6,865 KiB
dev cold-start	690 ms	627 ms

Verifications

• 🟢 yarn build && yarn preview + PWA activation -> I double-checked manually and everything works well (PWA registers well + the rest of the app just works perfectly fine)

• 🟢 yarn test:run → 176 passed

No new failures, the search one was already failing before and is currently not blocking anything either

• 🟢 yarn dev + HMR

No crazy improvements here but that was to be expected, still sub second. 👍🏻

Notes

• Vite 8 requires Node ^20.19.0 || >=22.12.0; CI is already on 22.x.
• The inlineDynamicImports option is deprecated warning originates from
  vite-plugin-pwa's internal service-worker build under Rolldown — the SW still
  builds and registers correctly. This is upstream for vite-plugin-pwa to resolve.
  • the lockfile was bumped with yarn 1.22.22 following the packageManager version in the package.json

Aka this part 👇🏻

• Pre-existing @vueuse/core pure-comment and dynamic-vs-static import warnings are
  unchanged (Rolldown just rewords them).

---

PS: disclaimer regarding the OHF AI Policy:

• Claude Code was used to speed 50% of the writing of this PR, I filled in the gaps + corrected a few metrics + added my personal touch to it 🤗
• it was also used to speed up local troubleshooting but everything was carefully reviewed by me + cross-checked multiple times