refactor(tests): restructure into layered POM architecture with Allure reporting

- Split framework into core/ (config, logger, db, driver factories, screenshot,
  allure integration) and pages/ (PO layer: base/admin/driver); flatten test
  files per platform (web/admin, app/driver_android, cross_end)
- Slim root conftest.py 656 -> ~100 lines: drop inline CN HTML report, add
  Allure severity mapping (p0/p1/p2 -> blocker/normal/minor) and
  environment.properties; support both tests.*-prefixed and bare imports
- Preserve TC-D2S-001/002 cross-end E2E cases with business logic unchanged,
  add allure epic/feature/story/step annotations
- Deduplicate: single makereport hook, shared failure-screenshot helpers,
  single SCREENSHOTS_DIR constant; deterministic auth-state role loading
- Move DB credentials from db_helper.py into test_config.yaml (database section)
- Move pytest.ini to repo root; switch reporting to allure-pytest
  (drop pytest-html/junitxml); update requirements.txt accordingly
- Delete deprecated scaffolding: test_freight_full_flow + 6 stale page
  objects, iOS/shipper empty shells, dead utils
- Fix flaky vxe-table action-row wait: wait for a visible td instead of
  hidden placeholder rows (fixed shipper-payment timeouts)
- Verified end-to-end against live env: both E2E cases pass (2 passed 3m12s);
  run artifacts (logs/screenshots/allure) included per repo convention

tests/core/config_loader.py

@@ -0,0 +1,38 @@
+"""配置加载器。
+
+从 tests/config/test_config.yaml 读取配置。
+
+Usage:
+    from tests.core.config_loader import load_config
+
+    config = load_config()
+    admin_url = config["admin"]["base_url"]
+    admin_phone = config["accounts"]["super_admin"]["phone"]
+
+各端通过 fixture 直接引用对应 section:
+    def test_xxx(admin_config):
+        page.goto(admin_config["base_url"])
+"""
+
+from pathlib import Path
+from typing import Any, Dict
+
+import yaml
+
+_CONFIG_PATH = Path(__file__).parent.parent / "config" / "test_config.yaml"
+_cache: Dict[str, Any] | None = None
+
+
+def load_config(force_reload: bool = False) -> Dict[str, Any]:
+    """加载测试配置（带缓存，force_reload=True 可强制重载）。"""
+    global _cache
+    if _cache is not None and not force_reload:
+        return _cache
+
+    if not _CONFIG_PATH.exists():
+        raise FileNotFoundError(f"配置文件不存在: {_CONFIG_PATH}")
+
+    with open(_CONFIG_PATH, encoding="utf-8") as f:
+        _cache = yaml.safe_load(f)
+
+    return _cache