docs(14-03): complete semantic cache implementation plan

- Created SUMMARY.md with implementation details
- Updated STATE.md with new decisions and session info
- Updated ROADMAP.md progress (1/6 plans complete)
- Marked COST-02 requirement complete

Duration: 1 min (72s)
Tasks: 1 (TDD: RED → GREEN)
Tests: 11 passed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -233,7 +233,7 @@ Phases execute in numeric order: 1 → 2 → ... → 12 → 13 → 14 → 15
 | 11. Stealth Fingerprinting | v1.4 | 2/2 | Complete | 2026-03-18 |
 | 12. SRT 简化处理器 | v1.5 | 2/2 | Complete | 2026-03-21 |
 | 13. 核心 LLM 分段功能 | 6/7 | Complete    | 2026-03-21 | - |
-| 14. 鲁棒性与成本控制 | v1.6 | 0/6 | Draft | 2026-03-23 |
+| 14. 鲁棒性与成本控制 | 1/6 | In Progress|  | 2026-03-23 |
 | 15. 输出优化与兼容性 | v1.6 | 0/0 | Not started | - |
 
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