phase4: entity_attachments table + DMS unified storage + attachment service rewritten + download via DMS

app/routes/attachments.py

@@ -93,12 +93,17 @@ async def download_attachment(
     if data is None:
         raise HTTPException(404, detail={"detail": "Attachment not found", "code": "not_found"})
 
-    file_path = data["file_path"]
-    # Use storage backend instead of os.path.isfile (P1.1 fix)
+    # Get storage path from DMS file via new unified service
+    storage_path = await attachment_service.get_attachment_download_path(
+        db, tenant_id, aid, user_id=user_id, is_system_admin=is_admin
+    )
+    if storage_path is None:
+        raise HTTPException(404, detail={"detail": "File not found in DMS", "code": "file_missing"})
+
     from app.core.storage import get_storage_backend
     storage = get_storage_backend()
     try:
-        file_bytes = await storage.load(file_path)
+        file_bytes = await storage.load(storage_path)
     except Exception:
         raise HTTPException(404, detail={"detail": "File not found in storage", "code": "file_missing"})