Propose the U5 action scope for user review

Why: The r2 U5 clause requires a human review of the action scope
before implementation; this draft grounds the decision in the current
command inventory and existing safety machinery.

Evidence: Source facts cited inline (builtin command list with risk
levels, DangerHigh inline-confirm flow with pendingStore, audit
envelope) verified against backend main on 2026-10-11.

Impact: Documents-only (new proposal + index entry); no code changes.

Refs: 2026-10-10-generative-ui-plugin.md (r2 U5); Dev task
feature/generative-ui-u5-scope

docs/proposals/INDEX.md

@@ -6,6 +6,10 @@
 
 ## 先看哪一份
 
+待用户裁定：[Generative UI U5 动作范围提案](2026-10-11-generative-ui-u5-action-scope.md)（2026-10-11）。
+r2 U5 条款要求先评审动作范围；本文给出 A/B/C/D 分类、审批挂接（复用既有 DangerHigh 确认卡与
+幂等）、排除项与验收线，待三点裁定后 U5 实施另行开任务。
+
 新增方向（已裁定取舍；U1 试验完成，r2 含结果与修订）：[Generative UI 调研与插件方案 r2](2026-10-10-generative-ui-plugin.md)。
 首试点为对话内完整分析页，交付采用可信编译插件；U1 试验限 MiniMax M3 + M2.7-highspeed、合成或脱敏材料、费用上限 ¥200，作为独立任务另行评审启动。
 此记录独立于下方历史核验快照，不改写历史方案/PR 数量或验收结论。