feat(widget): render recommendation attributes and stabilize product display contract

[digitalrisedorset]

Context:

Completes initial end-to-end rendering of recommendation results from the intent engine.

Changes:

• render product attributes dynamically (flatten attribute arrays)
• guard against undefined values (safe mapping)
• limit attribute display to reduce UI noise
• prepare structure for product card (attributes, labels, image placeholder)

Impact:

• aligns frontend with current engine response shape
• exposes contract assumptions between engine → widget

Open questions:

• should attribute display be deterministic or ranked?
• should UI rely on labels or value IDs?
• how do we handle missing images / incomplete products?

Next step:

• integrate image rendering from catalog API
• add add-to-cart interaction
• refine UX around intent context switching