Missing description attribute

Meta requires a non-empty description on every catalog item.

Description columns get dropped during feed transforms, or the source product had description-less SKUs that were exported anyway.

1. Confirm description has content for every product.
2. Add a feed rule: skip products missing description rather than submitting empty.
3. Aim for 100–500 characters of useful product info.

• Whitespace-only descriptions slip through; trim before validation