以标准桥式起重机样例图纸为基准，把页级、区域级、检索块、citation 和 GPT-first 问答调用链放进同一个工作台。
QD20T-28.5M-A5-GA · standard_bridge_crane · Rev R0
当前系统保留真实图纸文档链复用方向，同时把最小闭环样例直接挂出来，方便演示检索和 citation 回链。
Drawing ingestion reuses source_document -> document_parse -> document_extraction as the truth chain.
Seed demo already exposes page-level and region-level objects for a standard bridge crane sheet.
Demo regions carry OCR text, normalized text, and field payload for layout-critical dimensions.
Seed chunks model BGE-M3 + Qdrant style retrieval records and citation-ready snippets.
Drawing query API routes default requests through GPT-first provider resolution with citation persistence.