Collections Phase 3: Rich Views

Add kanban, gallery, and thread views to collections.

Scope

Group entries by a field (status, priority, custom field)

Drag-and-drop between columns updates the field value

Column headers show count

Configurable: which field to group by, column order

Card layout with entry title, summary/excerpt, optional image

Grid responsive to viewport width

Click card to navigate to entry

Chronological view for discussion-style collections

Entry body displayed inline (not just title)

Reply action creates new entry linked to parent

`__collection.yaml` `view` field specifies default view and per-view config

Frontend view switcher persists preference

Each view type has its own config schema (e.g., kanban: group_by field)

Collections Phase 1 (foundation — list/table views)