补齐手机登录页截图就绪检查（09-06-release-gate-integrity）

承接 09-17-company-loan-principal-repayment 的 N3 候选验证。
R106 手机首次截图前确认登录标题、账号输入和按钮已就绪，保留原全页截图、真实隔离后端登录、Worker 设置及全部巡检。

验证：受管完整 R106 文件 1 项通过，零失败/跳过/重试，14 张截图和报告生成；环境、源码一致性、清理、任务与治理检查通过。文档登记保留原有告警。

第四轮完整门禁为 371 通过、1 失败，原回执保留。Chromium 原始错误唯一成因尚未证明，此候选另行执行完整门禁。
独立代码复核、真实还款验收和发布待完成；仅本地提交。

.trellis/spec/hyb-oa/frontend-react-vite-design.md

@@ -170,6 +170,7 @@ and verification contracts. Do not copy broad aesthetic guidance from
 - At the narrowest viewport where the fixed sidebar appears, the main detail column is at least `560px`, the action column is at least `280px`, and the document has no horizontal overflow beyond a `2px` rendering tolerance.
 - Business identifiers and normal company-time date strings use DOM line-count or geometry assertions; `position: sticky` alone is not proof that the layout is usable.
 - A Playwright spec writes screenshots only to its own current output directory. Never reuse an archived Trellis task's evidence directory as a live test target.
+- Before a first screenshot after SPA navigation, assert the intended page identity and required controls are ready (for example, login heading and identifier visible, submit enabled). `goto`/load or font completion alone does not prove React has rendered the intended view. Preserve the original screenshot and test budget; do not convert capture failures into retries or assume a screenshot error proves authentication failed.
 - When comparing alignment inside an animated ancestor (for example `.page-scaffold`'s `page-reveal`), read all relevant `getBoundingClientRect()` values in one synchronous browser `evaluate`/`evaluateAll` callback. Sequential `boundingBox()` calls, or calls grouped with `Promise.all`, can observe different animation frames. Keep the original alignment assertions and pixel tolerances; do not hide the race with sleeps, retries or disabled page animations.
 
 ### 4. Validation & Error Matrix