chore: sync Parser PDF inventory reuse

[ZhiXiao-Lin]

Summary

• advance packages/office to feat(pdf): reuse validated page inventories Office#6 (ccf0665365adf08676efdfd38dc598a689e22f1d)
• advance crates/parser to A3S-Lab/Parser#2 (00516e1c6c61a1e07e8db9db606afae8df665f01)
• keep the monorepo synchronized with the browser-free cached PDF page inspection path

Validation

• Office PR docs(code): refactor A3S Code SDK docs — Node/Python tabs, new pages, slimmed reference #6 complete CI passed, including the optional real PDFium provider
• Parser PR session.stream内容输出异常 #2 MSRV plus Linux/macOS/Windows CI passed, including real PDFium render → OCR → overlay and agentic planning
• root diff contains only the two exact gitlink updates
• rebased onto current origin/main (bbc69308)