diff --git a/src/integrations/supabase/types.ts b/src/integrations/supabase/types.ts
index 6f153fb1..cff8ca73 100644
--- a/src/integrations/supabase/types.ts
+++ b/src/integrations/supabase/types.ts
@@ -1997,6 +1997,30 @@ export type Database = {
         }
         Relationships: []
       }
+      orphaned_images: {
+        Row: {
+          cloudflare_id: string
+          created_at: string
+          id: string
+          image_url: string
+          marked_for_deletion_at: string | null
+        }
+        Insert: {
+          cloudflare_id: string
+          created_at?: string
+          id?: string
+          image_url: string
+          marked_for_deletion_at?: string | null
+        }
+        Update: {
+          cloudflare_id?: string
+          created_at?: string
+          id?: string
+          image_url?: string
+          marked_for_deletion_at?: string | null
+        }
+        Relationships: []
+      }
       orphaned_images_log: {
         Row: {
           cleaned_up: boolean | null
@@ -5304,6 +5328,36 @@ export type Database = {
           },
         ]
       }
+      system_alerts: {
+        Row: {
+          alert_type: string
+          created_at: string
+          id: string
+          message: string
+          metadata: Json | null
+          resolved_at: string | null
+          severity: string
+        }
+        Insert: {
+          alert_type: string
+          created_at?: string
+          id?: string
+          message: string
+          metadata?: Json | null
+          resolved_at?: string | null
+          severity: string
+        }
+        Update: {
+          alert_type?: string
+          created_at?: string
+          id?: string
+          message?: string
+          metadata?: Json | null
+          resolved_at?: string | null
+          severity?: string
+        }
+        Relationships: []
+      }
       test_data_registry: {
         Row: {
           created_at: string
@@ -5935,6 +5989,15 @@ export type Database = {
         }
         Relationships: []
       }
+      system_health: {
+        Row: {
+          alerts_last_24h: number | null
+          checked_at: string | null
+          critical_alerts_count: number | null
+          orphaned_images_count: number | null
+        }
+        Relationships: []
+      }
     }
     Functions: {
       anonymize_user_submissions: {
@@ -6041,6 +6104,15 @@ export type Database = {
             }
             Returns: string
           }
+      create_system_alert: {
+        Args: {
+          p_alert_type: string
+          p_message: string
+          p_metadata?: Json
+          p_severity: string
+        }
+        Returns: string
+      }
       delete_entity_from_submission: {
         Args: {
           p_deleted_by: string
@@ -6195,7 +6267,7 @@ export type Database = {
       is_auth0_user: { Args: never; Returns: boolean }
       is_moderator: { Args: { _user_id: string }; Returns: boolean }
       is_superuser: { Args: { _user_id: string }; Returns: boolean }
-      is_user_banned: { Args: { _user_id: string }; Returns: boolean }
+      is_user_banned: { Args: { p_user_id: string }; Returns: boolean }
       log_admin_action: {
         Args: {
           _action: string
@@ -6239,6 +6311,7 @@ export type Database = {
         }
         Returns: undefined
       }
+      mark_orphaned_images: { Args: never; Returns: undefined }
       migrate_ride_technical_data: { Args: never; Returns: undefined }
       migrate_user_list_items: { Args: never; Returns: undefined }
       process_approval_transaction: {
@@ -6276,6 +6349,14 @@ export type Database = {
         }
         Returns: string
       }
+      run_system_maintenance: {
+        Args: never
+        Returns: {
+          details: Json
+          status: string
+          task: string
+        }[]
+      }
       set_config_value: {
         Args: {
           is_local?: boolean
diff --git a/supabase/migrations/20251107005923_5a6738b2-fe71-4152-9d6a-902aa51f1ce0.sql b/supabase/migrations/20251107005923_5a6738b2-fe71-4152-9d6a-902aa51f1ce0.sql
new file mode 100644
index 00000000..6d0ef17e
--- /dev/null
+++ b/supabase/migrations/20251107005923_5a6738b2-fe71-4152-9d6a-902aa51f1ce0.sql
@@ -0,0 +1,248 @@
+-- Phase 4: Application Boundary Hardening (Simplified)
+
+-- ============================================================================
+-- 1. IMAGE UPLOAD ORPHAN CLEANUP
+-- ============================================================================
+
+-- Track image uploads that haven't been associated with submissions after 24 hours
+CREATE TABLE IF NOT EXISTS orphaned_images (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  image_url TEXT NOT NULL,
+  cloudflare_id TEXT NOT NULL,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+  marked_for_deletion_at TIMESTAMPTZ
+);
+
+CREATE INDEX IF NOT EXISTS idx_orphaned_images_marked ON orphaned_images(marked_for_deletion_at) WHERE marked_for_deletion_at IS NOT NULL;
+
+-- Function to mark orphaned images (images uploaded but not in any submission after 24h)
+CREATE OR REPLACE FUNCTION mark_orphaned_images()
+RETURNS void
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+BEGIN
+  -- Mark images that haven't been used in submissions within 24 hours
+  INSERT INTO orphaned_images (image_url, cloudflare_id, marked_for_deletion_at)
+  SELECT DISTINCT 
+    si.url,
+    si.cloudflare_id,
+    now()
+  FROM submission_images si
+  WHERE si.created_at < now() - interval '24 hours'
+    AND NOT EXISTS (
+      SELECT 1 FROM content_submissions cs
+      WHERE cs.id = si.submission_id
+    )
+    AND NOT EXISTS (
+      SELECT 1 FROM orphaned_images oi
+      WHERE oi.cloudflare_id = si.cloudflare_id
+    );
+END;
+$$;
+
+-- ============================================================================
+-- 2. SLUG VALIDATION TRIGGERS
+-- ============================================================================
+
+-- Function to validate slug format (lowercase, alphanumeric with hyphens only)
+CREATE OR REPLACE FUNCTION validate_slug_format()
+RETURNS TRIGGER
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  IF NEW.slug IS NOT NULL THEN
+    -- Check format: lowercase letters, numbers, hyphens only
+    IF NEW.slug !~ '^[a-z0-9]+(-[a-z0-9]+)*$' THEN
+      RAISE EXCEPTION 'Invalid slug format: %. Slugs must be lowercase alphanumeric with hyphens only.', NEW.slug;
+    END IF;
+    
+    -- Check length constraints
+    IF length(NEW.slug) < 2 THEN
+      RAISE EXCEPTION 'Slug too short: %. Minimum length is 2 characters.', NEW.slug;
+    END IF;
+    
+    IF length(NEW.slug) > 100 THEN
+      RAISE EXCEPTION 'Slug too long: %. Maximum length is 100 characters.', NEW.slug;
+    END IF;
+    
+    -- Prevent reserved slugs
+    IF NEW.slug IN ('admin', 'api', 'auth', 'new', 'edit', 'delete', 'create', 'update', 'null', 'undefined') THEN
+      RAISE EXCEPTION 'Reserved slug: %. This slug cannot be used.', NEW.slug;
+    END IF;
+  END IF;
+  
+  RETURN NEW;
+END;
+$$;
+
+-- Apply slug validation to parks
+DROP TRIGGER IF EXISTS validate_parks_slug ON parks;
+CREATE TRIGGER validate_parks_slug
+  BEFORE INSERT OR UPDATE OF slug ON parks
+  FOR EACH ROW
+  EXECUTE FUNCTION validate_slug_format();
+
+-- Apply slug validation to rides
+DROP TRIGGER IF EXISTS validate_rides_slug ON rides;
+CREATE TRIGGER validate_rides_slug
+  BEFORE INSERT OR UPDATE OF slug ON rides
+  FOR EACH ROW
+  EXECUTE FUNCTION validate_slug_format();
+
+-- Apply slug validation to companies
+DROP TRIGGER IF EXISTS validate_companies_slug ON companies;
+CREATE TRIGGER validate_companies_slug
+  BEFORE INSERT OR UPDATE OF slug ON companies
+  FOR EACH ROW
+  EXECUTE FUNCTION validate_slug_format();
+
+-- ============================================================================
+-- 3. MONITORING & ALERTING INFRASTRUCTURE
+-- ============================================================================
+
+-- Critical alerts table for monitoring
+CREATE TABLE IF NOT EXISTS system_alerts (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  alert_type TEXT NOT NULL CHECK (alert_type IN (
+    'orphaned_images',
+    'stale_submissions',
+    'circular_dependency',
+    'validation_error',
+    'ban_attempt',
+    'upload_timeout',
+    'high_error_rate'
+  )),
+  severity TEXT NOT NULL CHECK (severity IN ('low', 'medium', 'high', 'critical')),
+  message TEXT NOT NULL,
+  metadata JSONB,
+  resolved_at TIMESTAMPTZ,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_system_alerts_unresolved ON system_alerts(created_at DESC) WHERE resolved_at IS NULL;
+CREATE INDEX IF NOT EXISTS idx_system_alerts_type ON system_alerts(alert_type, created_at DESC);
+
+-- Function to create system alert
+CREATE OR REPLACE FUNCTION create_system_alert(
+  p_alert_type TEXT,
+  p_severity TEXT,
+  p_message TEXT,
+  p_metadata JSONB DEFAULT NULL
+)
+RETURNS UUID
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+DECLARE
+  v_alert_id UUID;
+BEGIN
+  INSERT INTO system_alerts (alert_type, severity, message, metadata)
+  VALUES (p_alert_type, p_severity, p_message, p_metadata)
+  RETURNING id INTO v_alert_id;
+  
+  RETURN v_alert_id;
+END;
+$$;
+
+-- Enhanced ban attempt logging with alert
+CREATE OR REPLACE FUNCTION prevent_banned_user_submissions()
+RETURNS TRIGGER
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+DECLARE
+  v_user_banned BOOLEAN;
+  v_ban_reason TEXT;
+BEGIN
+  -- Check if user is banned
+  SELECT is_banned, ban_reason INTO v_user_banned, v_ban_reason
+  FROM profiles
+  WHERE id = NEW.submitted_by;
+  
+  IF v_user_banned THEN
+    -- Create alert for banned user attempt
+    PERFORM create_system_alert(
+      'ban_attempt',
+      'medium',
+      format('Banned user %s attempted to submit content', NEW.submitted_by),
+      jsonb_build_object(
+        'user_id', NEW.submitted_by,
+        'ban_reason', v_ban_reason,
+        'submission_type', NEW.entity_type,
+        'attempted_at', now()
+      )
+    );
+    
+    RAISE EXCEPTION 'Submission blocked: User account is banned. Reason: %', v_ban_reason;
+  END IF;
+  
+  RETURN NEW;
+END;
+$$;
+
+-- ============================================================================
+-- 4. MAINTENANCE FUNCTION
+-- ============================================================================
+
+-- Main maintenance function to run periodically
+CREATE OR REPLACE FUNCTION run_system_maintenance()
+RETURNS TABLE(
+  task TEXT,
+  status TEXT,
+  details JSONB
+)
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+DECLARE
+  v_orphaned_count INTEGER;
+BEGIN
+  -- Mark orphaned images
+  BEGIN
+    PERFORM mark_orphaned_images();
+    SELECT COUNT(*) INTO v_orphaned_count
+    FROM orphaned_images
+    WHERE marked_for_deletion_at IS NOT NULL
+      AND marked_for_deletion_at > now() - interval '1 hour';
+    
+    RETURN QUERY SELECT 
+      'mark_orphaned_images'::TEXT,
+      'success'::TEXT,
+      jsonb_build_object('count', v_orphaned_count);
+      
+    IF v_orphaned_count > 100 THEN
+      PERFORM create_system_alert(
+        'orphaned_images',
+        'medium',
+        format('High number of orphaned images detected: %s', v_orphaned_count),
+        jsonb_build_object('count', v_orphaned_count)
+      );
+    END IF;
+  EXCEPTION WHEN OTHERS THEN
+    RETURN QUERY SELECT 
+      'mark_orphaned_images'::TEXT,
+      'error'::TEXT,
+      jsonb_build_object('error', SQLERRM);
+  END;
+  
+  RETURN;
+END;
+$$;
+
+-- Grant necessary permissions
+GRANT EXECUTE ON FUNCTION mark_orphaned_images() TO authenticated;
+GRANT EXECUTE ON FUNCTION run_system_maintenance() TO authenticated;
+GRANT EXECUTE ON FUNCTION create_system_alert(TEXT, TEXT, TEXT, JSONB) TO authenticated;
+
+-- Create view for monitoring dashboard
+CREATE OR REPLACE VIEW system_health AS
+SELECT
+  (SELECT COUNT(*) FROM orphaned_images WHERE marked_for_deletion_at IS NOT NULL) as orphaned_images_count,
+  (SELECT COUNT(*) FROM system_alerts WHERE resolved_at IS NULL AND severity IN ('high', 'critical')) as critical_alerts_count,
+  (SELECT COUNT(*) FROM system_alerts WHERE resolved_at IS NULL AND created_at > now() - interval '24 hours') as alerts_last_24h,
+  now() as checked_at;
\ No newline at end of file