feat(competitions): save button, count at 3 or more, and /competitions/saved

[AnayDhawan]

Blocked by #199.

The client side of saving: a save button on cards and detail pages, the public count next to it, and a /competitions/saved page.

Files

• src/lib/competition-saves.ts - new, mirroring src/lib/user-places.ts
• src/components/competitions/save-button.tsx - 'use client'
• src/app/competitions/saved/page.tsx

Follow the existing Supabase client pattern exactly

src/lib/user-places.ts is the model (141 lines): requireClient() at :61-65 throws when the client is null, currentUserId() at :67-72, then thin fetch/create/delete wrappers. Copy that structure.

Functions needed:

fetchSavedCompetitionIds(): Promise<string[]>
saveCompetition(competitionId: string): Promise<void>
unsaveCompetition(competitionId: string): Promise<void>
fetchSaveCounts(): Promise<Record<string, number>>   // reads competition_stats, works signed out

The count rendering rule

Show the number only when it is 3 or more. Below that, render the save icon alone.

Do not reserve empty layout space for the hidden number. A permanently blank slot on every card for the first few months is worse than no slot at all. The button should be visibly narrower when there is no count, not a gap where a count would go.

Preview mode is a supported path, not an edge case

src/lib/supabase/config.ts:9-14 gates every call site and both client.ts and server.ts return null when the env vars are absent. Self-hosting without Supabase is first-class: the map, filters and calendar all work without it.

So: with no Supabase configured, the save button does not render at all, counts do not render, and /competitions/saved either redirects or shows the same "preview mode" card that src/app/login/login-form.tsx:29-44 uses. Nothing throws.

Signed out but Supabase configured: the button renders and prompts sign-in on click rather than silently doing nothing.

Optimistic update

Toggle the icon immediately, then reconcile. On failure, revert and surface a sonner toast; the repo already has sonner 2.0.7 wired up.

The saved page

Same card component as browse (#196), filtered to saved ids, sorted by soonest deadline. Empty state links to /competitions rather than being a dead end.

Acceptance criteria

• Save then reload: the state persists
• Count appears at 3, is absent at 2, and no gap is left behind
• Unsaving decrements the count
• Signed out: clicking prompts sign-in, no console error
• Supabase unconfigured: no save UI anywhere, no crash, npm run build still passes
• Failed write reverts the optimistic state and shows a toast
• /competitions/saved empty state is useful

[yakew7]

Implemented in 184b030, against the schema #199 defines (that migration still needs to be run by someone with dashboard access before this actually works end to end - see #199).

• src/lib/competition-saves.ts: fetchSavedCompetitionIds/saveCompetition/unsaveCompetition/fetchSaveCounts, mirroring user-places.ts's requireClient()/currentUserId() structure. fetchSaveCounts reads the public competition_stats table directly via createClient() (not requireClient()) so it works signed out, and returns {} rather than throwing when Supabase isn't configured, since the count is decorative.
• src/components/competitions/save-button.tsx: renders null outright when Supabase isn't configured (verified: npm run build still passes, and a running dev server serves the plain page with no save UI and no console error). Signed out, clicking redirects to /login?next=. Optimistic toggle, reverts with a sonner toast on failure. Count only renders at 3+; below that there's no reserved slot, just a narrower button.
• Wired into competition-card.tsx and competition-detail.tsx in place of the feat(competitions): browse page with search, category chips and filter panel #196/feat(competitions): detail page at /competitions/[slug] #198 placeholders. competitions-browser.tsx bulk-fetches saved ids and counts once for the whole grid and passes them down via initialSaved/initialCount, so 50 cards don't each independently query competition_stats; the detail page's single button has no bulk data to receive, so it fetches its own.
• src/app/competitions/saved/page.tsx: same CompetitionCard, filtered to saved ids, sorted by soonest deadline (sortByNextDate from feat(competitions): browse page with search, category chips and filter panel #196). Preview-mode card when Supabase is unconfigured (copies login-form.tsx's shape), a sign-in prompt when signed out, and an empty state linking back to /competitions when signed in with nothing saved yet.

18 new tests (Supabase and next/navigation mocked - see save-button.test.tsx, competition-saves.test.ts, and the saved page's tests) plus updated mocks in the existing card/detail tests. Full suite at 245 passing, typecheck/lint/build all clean.