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

output/allure-report/widgets/severity.json

@@ -0,0 +1 @@
+[{"uid":"ca43c608a8ccf0cf","name":"TC-D2S-001 司机APP接单到管理端核算打款完整流程","time":{"start":1786930187121,"stop":1786930276915,"duration":89794},"status":"passed","severity":"blocker"},{"uid":"f43b3909b7ed59be","name":"TC-D2S-002 司机APP接单到管理端核算打款-车队长全额收款流程","time":{"start":1786930283285,"stop":1786930372996,"duration":89711},"status":"passed","severity":"blocker"}]