Expose consent status API endpoint for service layer

Implement as a Supabase Edge Function in Deno (TypeScript). At the top of the handler, call createClient with the Authorization header from the request to get a user-scoped client — this ensures RLS from task-005 is applied. Use const { data, error } = await supabase.from('consent_grants').select('status, granted_at, consent_version, requires_reconsent').eq('mentor_id', mentorId).eq('org_id', orgId).maybeSingle() — maybeSingle() returns null instead of error when no row exists, allowing the 'pending' fallback. For the Dart client, use Supabase's functions.invoke('check-consent-status') method rather than raw http calls to get automatic JWT injection.

Define ConsentStatusResponse as an immutable Dart class with fromJson factory and copyWith. Keep the function stateless and free of any caching layer — consent status must always reflect the current database state.

Unit tests for the Dart ConsentStatusClient: mock HTTP responses for each status variant (granted, denied, revoked, pending), assert correct ConsentStatusResponse parsing, assert ConsentUnauthorizedException on 403, assert ConsentAuthException on 401, assert network error surfaced as ConsentNetworkException. Integration tests against local Supabase (supabase start): deploy function locally, call with valid JWT for each role, assert correct status returned for each consent state. Load test: 50 concurrent requests to confirm p95 < 300ms. Test cold start by restarting the function and measuring first-call latency.