feat(ong-den): rebuild estimate from appraised TD workbook + BIM source-grounding tests

- tools/estimation/ong_den_rebuild_estimate.py: doc nguyen van du toan TD, tu doi soat A1/B1/C1 THKP, ghep Phu luc 01 theo chuoi ma (66 dong khop, 7 dong chi co trong TD), luong hoa rui ro H1-H6 bang don gia TD

- tests: grounding BIM viewer theo DWG/TD/Gantt; fix marker asyncio->anyio