Fix: Correct idempotency migration issues

Corrected database migration for idempotency keys to address security warnings related to function search path and security definer views.

supabase/migrations/20251106162919_f5cf07ce-0e36-4762-b4a4-213ee6bd71e1.sql

@@ -0,0 +1,48 @@
+-- Fix security warnings for idempotency system
+
+-- 1. Fix Function Search Path: Add explicit search_path to cleanup function
+CREATE OR REPLACE FUNCTION cleanup_expired_idempotency_keys()
+RETURNS INTEGER
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path TO 'public'
+AS $$
+DECLARE
+  deleted_count INTEGER;
+BEGIN
+  DELETE FROM submission_idempotency_keys
+  WHERE expires_at < now() - interval '1 hour';
+  
+  GET DIAGNOSTICS deleted_count = ROW_COUNT;
+  
+  RETURN deleted_count;
+END;
+$$;
+
+-- 2. Fix Security Definer View: Add RLS to idempotency_stats view
+-- Drop and recreate with proper security
+DROP VIEW IF EXISTS idempotency_stats;
+
+CREATE VIEW idempotency_stats 
+WITH (security_invoker=true)
+AS
+SELECT
+  DATE_TRUNC('hour', created_at) AS hour,
+  status,
+  COUNT(*) AS total_requests,
+  COUNT(DISTINCT moderator_id) AS unique_moderators,
+  AVG(duration_ms) AS avg_duration_ms,
+  PERCENTILE_CONT(0.95) WITHIN GROUP (ORDER BY duration_ms) AS p95_duration_ms
+FROM submission_idempotency_keys
+WHERE created_at > now() - interval '7 days'
+GROUP BY DATE_TRUNC('hour', created_at), status
+ORDER BY hour DESC, status;
+
+COMMENT ON VIEW idempotency_stats IS 'Monitoring view for idempotency key performance and usage statistics (admin/moderator access only via RLS)';
+
+-- Enable RLS on the view
+ALTER VIEW idempotency_stats SET (security_invoker=true);
+
+-- Add RLS policy for the view (admins and moderators only)
+-- Note: Views use the underlying table's RLS, so moderators/admins who can access 
+-- submission_idempotency_keys can access this view