Shopify metafields

• Define metafields with a clear namespace.key and the tightest type that fits (e.g. single_line_text_field, rich_text_field, list.*).
• Read them in Liquid via {{ product.metafields.namespace.key }} and expose settings as dynamic sources so merchants can bind them in the theme editor without touching code.
• Use metaobjects for structured, reusable content (size guides, FAQs) and render entries with {{ metaobject.field }}.
• Always guard with {% if %} — metafields are frequently empty.