Inventory Generate

Batch-generate typed visual inventory from the character's identity. categories ⊆ {wardrobe, accessory, prop, place, scene}; up to ``count_per_category`` each, capped at 8 images/batch (each is a metered generation). Results land in GET .../visual-inventory typed by category — immediately active by default, or as candidates when ``hold_for_review`` is true (then approve via PATCH visual-assets). Requires an active identity + ``profile.identity_anchors`` and an open sandbox ``session_id``. App-scoped; 404 if not owned.