Fix: Implement pipeline error handling

Implement comprehensive error handling and robustness measures across the entire pipeline as per the detailed plan. This includes database-level security, client-side validation, scheduled maintenance, and fallback mechanisms for edge function failures.

supabase/migrations/20251107044746_d2d30465-685b-432a-a6ca-b2b8e46935b9.sql

@@ -0,0 +1,18 @@
+-- Phase 1: Critical Security Fixes for Sacred Pipeline
+-- Fix 1.1: Attach ban prevention trigger to content_submissions
+CREATE TRIGGER prevent_banned_submissions
+  BEFORE INSERT ON content_submissions
+  FOR EACH ROW
+  EXECUTE FUNCTION prevent_banned_user_submissions();
+
+-- Fix 1.2: Add RLS policy to prevent banned users from submitting
+CREATE POLICY "Banned users cannot submit"
+ON content_submissions
+FOR INSERT
+TO authenticated
+WITH CHECK (
+  NOT EXISTS (
+    SELECT 1 FROM profiles
+    WHERE user_id = auth.uid() AND banned = true
+  )
+);