rebrand: PropDataGuard → DataPointer

- App name: PropDataGuard → DataPointer
- Frontend title: 财险数据分级分类平台 → 数据分类分级管理平台
- LocalStorage keys: pdg_token/pdg_refresh → dp_token/dp_refresh
- Package name: prop-data-guard-frontend → data-pointer-frontend
- Project config: admin@propdataguard.com → admin@datapo.com
- Celery app name: prop_data_guard → data_pointer
- Layout logo, login title, page title all updated

backend/scripts/generate_test_data.py

@@ -1,5 +1,5 @@
 """
-Generate test data for PropDataGuard system.
+Generate test data for DataPointer system.
 Targets: 10000+ records across all tables.
 """
 import sys
@@ -110,7 +110,7 @@ for i in range(80):
     username = f"user{i+2:03d}"
     user = User(
         username=username,
-        email=f"{username}@propdataguard.com",
+        email=f"{username}@datapo.com",
         hashed_password=get_password_hash("password123"),
         real_name=real,
         phone=random_phone(),