feat(onboarding): skippable first-run questionnaire that feeds the product

[AnayDhawan]

Blocked by #203.

A short questionnaire after first sign-in: graduation year, board, field, country, and how they found StudyMap.

Files

• src/app/onboarding/page.tsx
• src/components/onboarding/onboarding-flow.tsx - 'use client'
• src/lib/user-profile.ts - mirroring src/lib/user-places.ts

The questions

1. When are you graduating? Current year through +6.
2. What board are you on? IB, IGCSE, CBSE, ICSE, A-Levels, AP, State board, Other.
3. What field? STEM, Humanities, Commerce, Arts, Undecided.
4. Which country? The 13 with competition pathways, plus Other.
5. How did you find StudyMap? GitHub, Google, Instagram, Friend or school, Reddit, Other with a free-text box.

Every answer has to change something the user sees

This is the acceptance bar, not a nice-to-have. A questionnaire whose answers feed nothing is a survey wearing an onboarding costume, and it taxes signup for our benefit rather than theirs.

• board filters which exam sessions the calendar shows by default. src/lib/exam-dates.ts:157-159 already has eventsByBoard, so this is small.
• country selects the default country track on competition detail pages (feat(competitions): detail page at /competitions/[slug] #198) and in the calendar (feat(competitions): calendar events, country selector, non-empty default #201).
• graduation_year orders deadline relevance: a 2027 leaver should see 2027 cycles first.
• referral_source is the one question that buys the user nothing. It is analytics. Put it last, make it clearly optional, and do not block completion on it.

Skippable, resumable, not a gate

• Trigger on first sign-in when no profile row exists. Redirect from the auth callback, not from a global layout check that runs on every navigation.
• A visible "Skip for now" on every step, and a skip must not re-prompt on the next sign-in. Record that the user was asked, otherwise skipping is indistinguishable from never having been offered it.
• Persist per step, so closing the tab halfway keeps what was answered. Every column is nullable for exactly this reason.
• Reachable later from the account page so a skipper can fill it in. Note feat: unified account/profile page for signed-in users #98 covers a unified account page and is the natural edit surface for this same table; coordinate rather than building two.
• Never block access to the map, calendar or competitions.

Preview mode

With Supabase unconfigured there is no auth, so /onboarding should not be reachable and nothing should call it. Follow the isSupabaseConfigured() gate at src/lib/supabase/config.ts:9-14 the way every other Supabase call site does.

Acceptance criteria

• Appears once after first sign-in, not on every sign-in
• Skipping on any step never re-prompts
• Closing mid-flow and returning resumes where it left off
• Answers land in user_profiles and are visible via select * from user_profiles in the dashboard
• Changing board visibly changes the calendar's default exam sessions
• Changing country visibly changes the default country track on a detail page
• Keyboard operable start to finish, focus moves to each new step
• Supabase unconfigured: route is unreachable, nothing throws
• Nothing in the product is blocked by not completing it

[yakew7]

Implemented in b9ceaa1:

• src/lib/user-profile.ts: fetch/upsert against user_profiles, mirroring user-places.ts (requireClient guard, thin wrappers), plus hasSeenOnboarding/ensureProfileRow, boardToExamBoards, and profileCompetitionCountry helpers.
• src/app/onboarding/page.tsx + src/components/onboarding/onboarding-flow.tsx: 5-step questionnaire (graduation year, board, field, country, referral source). Each step persists on Next; "Skip for now" is on every step; a blank row is written on mount (ensureProfileRow) so a full skip still counts as "asked"; a returning user resumes at the first unanswered step; focus moves to each new step's heading.
• src/app/auth/callback/route.ts and the signInWithPassword path in src/app/login/login-form.tsx both redirect first-time signed-in users to /onboarding before next (password sign-in never goes through the callback route, so it needed its own check). Both fail open on any error, including a missing table.
• src/app/calendar/CalendarView.tsx: profile board narrows the default exam-session list (only IB/IGCSE have real exam-date data to filter by; everything else shows all boards, with a toggle either way), profile country sets the default competition-country selector.
• src/app/competitions/[slug]/page.tsx + src/components/competitions/competition-detail.tsx: pass the profile's country as CountryTrackList's defaultCountry.
• src/app/account/AccountView.tsx: shows current answers with a link to /onboarding to edit them (per feat: unified account/profile page for signed-in users #98 coordination note in this issue).

Depends on #203's user_profiles table, not yet applied to any live Supabase project in this environment. Every read/write here fails open rather than throwing or blocking sign-in, same as #200/#201 were built against #199's not-yet-applied table. Once #203 is run, this should work end to end without further code changes.

Tests: npm run typecheck, npm run lint, npm run test:unit (271 passing, added src/lib/user-profile.test.ts and src/components/onboarding/onboarding-flow.test.tsx), and npm run build all pass.