fix: all imports → relative (from .xxx) — no stdlib site conflict

site/routes/upload_bp.py

@@ -1,9 +1,9 @@
 """Upload blueprint — загрузка, конвертация, распаковка."""
 import io, os, base64, hashlib, zipfile, tempfile, subprocess
 from flask import Blueprint, request, jsonify, send_file
-from site.services.parse import parse_file
-from site.db import documents
-from site.config import MAX_CONTENT_LENGTH
+from .services.parse import parse_file
+from .db import documents
+from .config import MAX_CONTENT_LENGTH
 
 upload_bp = Blueprint("upload", __name__)