Add native Windows compatibility layer

routes/upload_routes.py

@@ -105,7 +105,7 @@ def setup_upload_routes(upload_handler):
         info = None
         uploads_db = os.path.join(UPLOAD_DIR, "uploads.json")
         if os.path.exists(uploads_db):
-            with open(uploads_db) as f:
+            with open(uploads_db, encoding="utf-8") as f:
                 db = json.load(f)
             info = next((fi for fi in db.values() if fi["id"] == file_id), None)
             if info:
@@ -153,7 +153,7 @@ def setup_upload_routes(upload_handler):
         info = None
         uploads_db = os.path.join(UPLOAD_DIR, "uploads.json")
         if os.path.exists(uploads_db):
-            with open(uploads_db) as f:
+            with open(uploads_db, encoding="utf-8") as f:
                 db = json.load(f)
             info = next((fi for fi in db.values() if fi["id"] == file_id), None)
         return info
@@ -199,7 +199,7 @@ def setup_upload_routes(upload_handler):
         cache_path = _vision_cache_path(file_id)
         if not force and os.path.exists(cache_path):
             try:
-                with open(cache_path) as f:
+                with open(cache_path, encoding="utf-8") as f:
                     return {"text": f.read(), "cached": True}
             except Exception as e:
                 logger.warning(f"Vision cache read failed for {file_id}: {e}")
@@ -210,7 +210,7 @@ def setup_upload_routes(upload_handler):
             logger.error(f"Vision analysis failed for {file_id}: {e}")
             raise HTTPException(500, f"Vision analysis failed: {e}")
         try:
-            with open(cache_path, "w") as f:
+            with open(cache_path, "w", encoding="utf-8") as f:
                 f.write(text)
         except Exception as e:
             logger.warning(f"Vision cache write failed for {file_id}: {e}")
@@ -238,7 +238,7 @@ def setup_upload_routes(upload_handler):
         text = (body or {}).get("text", "")
         if not isinstance(text, str):
             raise HTTPException(400, "text must be a string")
-        with open(_vision_cache_path(file_id), "w") as f:
+        with open(_vision_cache_path(file_id), "w", encoding="utf-8") as f:
             f.write(text)
         return {"ok": True}