asset-spec

If no argument is provided, check whether design/assets/entity-inventory.md exists:

• If it exists: read it, find the first entity or screen with status "Needed" but no spec file yet, and use AskUserQuestion:
  • Prompt: "The next unspecced item is [name]. Generate specs for it?"
  • Options: [A] Yes — spec [name] / [B] Pick a different item / [C] Stop here
• If no entity inventory: check design/assets/asset-manifest.md. If manifest exists, same flow above but reading from manifest.
• If neither exists: start the Entity & Screen Inventory flow (Phase 0b below) rather than failing.

Phase 0b: Entity & Screen Inventory (runs when no arguments and no existing inventory)

This flow produces design/assets/entity-inventory.md — the master list of everything the game needs visually. Run once before asset spec work begins.