fix(dispatch): render scalar-array list responses as a named column

[phil-accelbyte]

Problem

A list body shaped like {"regions": ["us-east-1", ...]} — an object whose single array holds bare strings — rendered as an empty list. detect_shape unwrapped it to a bare array, then build_list_table derived columns only from object fields, found none, and returned early with zero rows. So ags ams info list-regions showed nothing, even though the data was present (the workflow dynamic-enum picker, which reads $.regions from the raw body, listed the regions fine).

Fix

Thread the unwrapped object key through ResponseShape::Array so the scalar case renders as a single column named after that key (e.g. Regions), falling back to the collection noun for bare top-level arrays. A genuinely empty array still renders as the empty-collection view.

Tests

• An array of bare scalars renders as a single named column, not dropped.
• End-to-end: a {"regions": [strings]} body shapes into a Collection with a single Regions column (regression guard for the empty-list bug).