Fix foreign key cascades and add validation for missing AR fields

- Enable SQLite foreign key constraints to properly cascade deletes
- Add validation to prevent adding products when no AR fields configured
- Display helpful warnings on product pages when fields are missing
- Redirect users to AR field configuration when needed

src/app/blueprints/admin/routes.py

@@ -10,6 +10,11 @@ def add_product(tenant_id):
     """Add a new product"""
     custom_fields = ARFieldModel.get_all(tenant_id)
 
+    # Prevent adding products if no fields are configured
+    if not custom_fields:
+        flash('Cannot add products. Please configure AR fields first.', 'warning')
+        return redirect(url_for('admin.manage_ar_fields', tenant_id=tenant_id))
+
     if request.method == 'POST':
         product_id = request.form.get('product_id')
 

src/app/models/base.py

@@ -8,6 +8,8 @@ def get_db():
     db_path = current_app.config['DATABASE_PATH']
     conn = sqlite3.connect(db_path)
     conn.row_factory = sqlite3.Row
+    # Enable foreign key constraints
+    conn.execute('PRAGMA foreign_keys = ON')
     try:
         yield conn
     finally:

src/app/templates/admin/add_product.html

@@ -10,6 +10,21 @@
                 <h2>Add New Product</h2>
             </div>
             <div class="card-body">
+                {% if not custom_fields %}
+                <div class="alert alert-warning" role="alert">
+                    <h4 class="alert-heading"><i class="bi bi-exclamation-triangle-fill me-2"></i>No Fields Configured</h4>
+                    <p>Unable to add products. You must configure custom AR fields before adding products.</p>
+                    <hr>
+                    <p class="mb-0">
+                        <a href="/{{ tenant_id }}/ar_fields" class="btn btn-primary">
+                            <i class="bi bi-gear-fill me-1"></i>Configure AR Fields
+                        </a>
+                        <a href="/{{ tenant_id }}/" class="btn btn-secondary ms-2">
+                            <i class="bi bi-arrow-left me-1"></i>Back to Products
+                        </a>
+                    </p>
+                </div>
+                {% else %}
                 <form action="/{{ tenant_id }}/add" method="POST" enctype="multipart/form-data">
                     <div class="mb-3">
                         <label for="product_id" class="form-label">Product ID *</label>
@@ -71,6 +86,7 @@
                         <button type="submit" class="btn btn-primary">Add Product</button>
                     </div>
                 </form>
+                {% endif %}
             </div>
         </div>
     </div>

src/app/templates/index.html

@@ -16,6 +16,18 @@
             <hr class="my-4">
             
             <div class="mt-4">
+                {% if not custom_fields %}
+                <div class="alert alert-warning" role="alert">
+                    <h4 class="alert-heading"><i class="bi bi-exclamation-triangle-fill me-2"></i>No AR Fields Configured</h4>
+                    <p>Before you can add products, you need to configure custom AR fields that define what information is returned for each product.</p>
+                    <hr>
+                    <p class="mb-0">
+                        <a href="/{{ tenant.id }}/ar_fields" class="btn btn-primary">
+                            <i class="bi bi-gear-fill me-1"></i>Configure AR Fields
+                        </a>
+                    </p>
+                </div>
+                {% else %}
                 <div class="d-flex justify-content-between align-items-center mb-3">
                     <h2>Products</h2>
                     <div>
@@ -27,7 +39,7 @@
                         </a>
                     </div>
                 </div>
-                
+
                 {% if products %}
                 <div class="table-responsive">
                     <table class="table table-striped table-hover">
@@ -91,6 +103,7 @@
                     <i class="bi bi-info-circle"></i> No products available yet. Click "Add New Product" to get started.
                 </div>
                 {% endif %}
+                {% endif %}
             </div>
 
             <div class="mt-4">