Implement Badge Criteria Edge Function

Structure the Edge Function as a standard Deno HTTP handler in functions/badge-criteria/index.ts. Use the @supabase/supabase-js client initialised with the request's JWT for RLS-enforced reads, and a separate admin client (SERVICE_ROLE_KEY from Deno.env) only for writes that require bypassing RLS (e.g., inserting earned badges). Port the badge evaluation criteria logic from the Dart BadgeEvaluationService into a TypeScript module at functions/_shared/badgeEvaluation.ts — shared across Edge Functions to avoid drift. Use Promise.all() for parallel badge award calls but wrap each in a try/catch to collect partial failures.

Emit Realtime events by inserting a row into a badge_events table with columns: mentor_id, badge_id, org_id, awarded_at — the Flutter client subscribes to this table filtered by mentor_id. Set a function timeout of 10 seconds in supabase/config.toml. Document all environment variables required (SERVICE_ROLE_KEY, SUPABASE_URL) in a .env.example file adjacent to the function.

Write integration tests using Supabase local development (supabase start) and the Deno test runner: (1) POST with valid JWT and a mentorId that qualifies for two badges returns 200 with both badge IDs in awarded array, (2) POST with expired JWT returns 401, (3) POST where mentorId mismatches JWT sub returns 403, (4) evaluation returning zero new badges returns 200 with empty awarded array, (5) badge-award-service failure for one badge is captured in errors array without aborting remaining awards. Seed test database with known badge definitions, mentor stats, and earned badges for deterministic evaluation. Verify Realtime events are emitted by subscribing to the badge_events table in the test and asserting the event payload matches awarded badge IDs. All tests must run against local Supabase instance — no calls to production.