feat(embed,ui04): E07 acceptance — matrix completion, hostile-CSS hardening, measurements and record closure

- E07 e2e (7 cases): 4-viewport fixed size, narrow shrink + dual-slot 12px stack, single/static + empty state + two-photo loop copies, broken-thumb drop, reducedMotion stop with manual arrows, forged postMessage rejected, hostile CSS (!important box-sizing/border) with inline-important countermeasures + duplicate script dedup
- loader v2: geometry-critical properties upgraded to inline !important (beats host stylesheet !important)
- pre-existing fixes: likes.spec view-count assertion vs concurrent session's AlbumHeader unicode icons (toContainText); embed-v2 host port moved to 3998 (3999 collides with embed-crossorigin under parallel full runs); prettier formatting of two concurrent-session files (formatting-only)
- evidence: matrix EMB-A01..A16 closed in acceptance record (mechanism-level items honestly marked), measurements (loader v2 9885B/gzip 3959B, first-load 1 GET + 1 WS, DOM<=16), refreshed screenshots/recordings, master plan UI-04 note
- regression: root lint/typecheck/test 12 packages green; embed suites 43/43; admin embed-slots 5/5; journey pre-existing env failure reproduced at clean HEAD (registered)

Co-Authored-By: Claude Code <noreply@anthropic.com>

docs/plans/2026-09-17-实施总纲.md

@@ -118,6 +118,14 @@ Schema 所有权：国内库表（users、albums、photos、upload_sessions、ou
 > 映射、10 张 after 截图、web 426 单测 + 364 e2e + mobile analyze 0 + 397 测试全绿
 > （合计 1187，mobile +56）；320/430/平板/横屏/文字缩放与 iOS/真机关口随 G2 执行。）
 
+**UI-04（2026-09-22）**：嵌入组件 v2「垂直照片流窗」完成——PC/手机固定
+195×280、连续上滚（16px/s 可配 8-32）、真实点赞心形气泡（WS 只读）、无
+header/footer、右上收起；新契约字段 displayMode/scrollSpeed/reactionsEnabled
+（可选扩展，旧客户端零影响）；新入口 /embed/v2/loader.js（v1 冻结保留）；
+管理端模式配置 + 真实组件预览（/embed-preview 样例数据注入，§8.2 隔离）。
+验收记录见 docs/plans/progress/UI04-验收记录.md（EMB-A01…A16 矩阵、
+录屏/测量证据；A10 真断线演练等机制级项随 P5）。不改变 P5 待办与关口。
+
 阶段顺序 P1 → P2 → P3 → P4a → P4b → P5。P3 与 P4a 在 P2 契约稳定后可并行；P4b 依赖 P2 的公开列表契约与同步通道（展示位事件扩展），其 T15 全端语言验收还需 P3 完成；P5 依赖全部前序。
 
 每阶段出口执行统一回归门：lint + typecheck + 单元 + 集成 + E2E 全绿，并产出《阶段验收记录》（docs/plans/progress/，逐项对照 A 编号登记证据与未尽事项）。