fix(portal): self-recover stale tabs on any chunk load failure, offer reload on the 500 page

[devin-ai-integration]

Summary

Stale tabs/PWAs that lazy-load a content-hashed chunk deleted by a deploy could get stuck on the 500 ErrorPage: vite:preloadError only fires for imports that go through Vite's preload helper, and the existing buttons (navigate(-1) / navigate("/")) never fetch a fresh shell. Code-only; no infra changes.

stale-chunk-reload.ts:

• isChunkLoadError(message) matches /failed to fetch dynamically imported module/i, /error loading dynamically imported module/i, /importing a module script failed/i, /chunkloaderror/i.
• reloadOnce() factors out the RELOAD_STAMP_KEY / RELOAD_COOLDOWN_MS (10s, sessionStorage) guard + window.location.reload().
• installStaleChunkReload() now wires three triggers through reloadOnce(): vite:preloadError (unchanged, preventDefault first), plus unhandledrejection and error listeners that fire only when isChunkLoadError matches the reason / error message. Shared cooldown prevents reload loops if the fresh build also fails.

ErrorPage.tsx: when the 500 detail matches isChunkLoadError, render a primary "A new version is available — reload" button calling window.location.reload() above the existing back/home buttons.

Verified: npm run lint, npm run format:check, npm run build in client/portal.

Link to Devin session: https://app.devin.ai/sessions/1348deb2b5ac4efb99688d4995a51f47
Open in Devin Desktop: https://app.devin.ai/desktop/session/1348deb2b5ac4efb99688d4995a51f47?variant=devin
Requested by: @balebbae

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring