Record approved U3 design and r0.5 implementation plan

Why: The user approved the r0.5 written design for detailed planning; the resulting plan must be traceable from the Dev task and project entry.

Evidence: Documents 25a561b passed link and diff checks; staged Dev make test completed exit 0 through make evidence in the task card.

Impact: Pin plan and approval status only. Product code, new paid model calls, merge, and deployment remain not run.

Refs: U3 r0.5 plan; Documents PR #95; Dev PR #512

PROJECT.md

@@ -70,5 +70,5 @@ U2 起实施与部署分别评审。
 
 - [渐进工作台界面重设计 r0.2](modules/documents/docs/proposals/2026-10-12-work-companion-ui-design.md)：用户已授权连续实施；[计划 r1](modules/documents/docs/proposals/2026-10-12-work-companion-ui-plan.md)覆盖任务摘要、对话/输入、窄屏和真实状态投影；进展见对应任务卡。
 
-- [快慢通道 U2/U3 实施计划 r0.1](modules/documents/docs/proposals/2026-10-13-fast-slow-u2-u3-plan.md)：r0.2、r0.3、r0.4 的真实模型质量均 FAIL；r0.4 的书面设计、实施计划和零付费阶段 6 已获评审，一次性付费 A01 已执行并停止。八个 PR 保持草稿，未合入或部署。用户已认可下一版方向，[r0.5 安全终态证据与可信快通道反馈书面设计](modules/documents/docs/proposals/2026-10-14-fast-slow-u3-r05-terminal-evidence-and-fast-feedback-design.md)待人工评审；不授权代码、付费复验或合入。详见[核验报告](modules/documents/docs/reports/2026-10-13-fast-slow-u2-u3-validation.md)。
+- [快慢通道 U2/U3 实施计划 r0.1](modules/documents/docs/proposals/2026-10-13-fast-slow-u2-u3-plan.md)：r0.2、r0.3、r0.4 的真实模型质量均 FAIL；r0.4 的书面设计、实施计划和零付费阶段 6 已获评审，一次性付费 A01 已执行并停止。八个 PR 保持草稿，未合入或部署。[r0.5 安全终态证据与可信快通道反馈书面设计](modules/documents/docs/proposals/2026-10-14-fast-slow-u3-r05-terminal-evidence-and-fast-feedback-design.md)已获批准，[详细实施计划](modules/documents/docs/proposals/2026-10-14-fast-slow-u3-r05-terminal-evidence-and-fast-feedback-implementation-plan.md)待阶段 5 人工评审；不授权代码、付费复验或合入。详见[核验报告](modules/documents/docs/reports/2026-10-13-fast-slow-u2-u3-validation.md)。
 - [系统项目、成员工作入口与私域协作闭环 r1](modules/documents/docs/proposals/2026-10-13-system-project-membership.md)：2026-10-13 用户批准阶段 1–9 连续推进；统一全局项目身份与名称、成员个人会话、每项目两树一网和私域权限；当前组合验证/CI/tag 消费推进中，部署与线上修复未授权。