photoshop_list_documents

List every open Photoshop document with id, dimensions, and which tab is active (read-only). Use when: multiple documents are open and you need document_id before switching tabs or closing a specific file. Do NOT use when: you only need the active document — use photoshop_get_document_info or photoshop_get_state. Returns: JSON { ok, summary, details: { count, documents[], active_document_id, context } }. Preconditions: none (safe when zero documents open). Side effects: none.