Give the new error boundary pages a focus target matching the app's route-change pattern

[Abidoyesimze]

Summary

onboarding/error.tsx, profile/error.tsx, and (errors)/server-error/page.tsx render ErrorPage inside a plain div with no id/tabIndex. The app's DashboardShell moves focus to #main-content on every pathname change, but these routes sit outside that route group and never get it — the header's skip-link also resolves to nothing on these pages.

Affected files

• src/app/onboarding/error.tsx
• src/app/profile/error.tsx
• src/app/(errors)/server-error/page.tsx
• src/components/ui/ErrorPage.tsx

Tasks

• Give ErrorPage's wrapper the MAIN_CONTENT_LANDMARK_ID id (or an equivalent) and move focus to it on mount.
• Verify the header's skip-to-main-content link resolves correctly on these three routes.

Acceptance criteria

• Scope is limited to the files listed (or agreed alternatives in the PR).
• Change is verifiable: tests, screenshots, or written QA steps in the PR.
• No behavior regressions in related user flows.
• No new duplicate abstractions without a one-line rationale in the PR.

Suggested labels

a11y, routing

Notes

Sourced from the 2026-07-25 round-2 follow-up audit of the frontend codebase at commit 779e531, run after the first 60-issue audit batch (#525-#584) was substantially resolved. Verified against current file content at time of writing.