Present the U3 r0.3 zero-paid review candidate

Why: The approved implementation and mechanism validation are complete, while the real-model quality gate remains unrun.

Evidence: Dev ef6f650 make test/build exit 0 with imported SELF receipt; Backend 5f53f80 independent code replay and v10 PostgreSQL/HTTP receipts are linked in the card.

Impact: Update task/project status for human stage-6 review; no provider request, merge or deployment.

Refs: Dev PR #512; Documents PR #95

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 唯一获批 A01 已执行，因无依据的分期归属判断，真实模型质量仍 FAIL，尚未合入或部署。[有依据的阶段判断设计 r0.3](modules/documents/docs/proposals/2026-10-13-fast-slow-u3-r03-evidence-backed-judgments-design.md)与[详细实施计划](modules/documents/docs/proposals/2026-10-13-fast-slow-u3-r03-evidence-implementation-plan.md)已获用户批准，零付费实施与验证进行中；新付费样本仍须另行批准。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 唯一获批 A01 已执行，因无依据的分期归属判断，真实模型质量仍 FAIL，尚未合入或部署。[有依据的阶段判断设计 r0.3](modules/documents/docs/proposals/2026-10-13-fast-slow-u3-r03-evidence-backed-judgments-design.md)与[详细实施计划](modules/documents/docs/proposals/2026-10-13-fast-slow-u3-r03-evidence-implementation-plan.md)已获用户批准；零付费实现、机制验证和独立代码复审完成，待阶段6人工审阅与单独付费样本资源批准。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。