docs: rename SDD folders u6u-* → arcrun-* + update cross-refs

對應 SDD arcrun/.agents/specs/llm-interface/ M5.6（之前列為 backlog 連動）。
leo 2026-05-16 拍板 u6u 整體退場後，順手把兩個 SDD 也改名。

- .agents/specs/u6u-core-mvp/ → arcrun-core-mvp/
- .agents/specs/u6u-platform-evolution/ → arcrun-platform-evolution/
- CLAUDE.md / .claude/rules/00-sdd-protocol.md / 04-current-progress.md /
  llm-interface SDD 內所有跨 SDD 引用同步更新

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.agents/specs/arcrun-platform-evolution/design.md

@@ -773,7 +773,7 @@ type DTNEntry struct {
 使用 `fast-check`（已在 tech stack 中），每個屬性測試標記格式：
 
 ```typescript
-// Feature: u6u-platform-evolution, Property N: {property_text}
+// Feature: arcrun-platform-evolution, Property N: {property_text}
 it.prop([fc.record({ id: fc.string(), version: fc.string(), ... })])(
   'Property 1: 合約格式完整性',
   (contract) => {

.agents/specs/llm-interface/design.md

@@ -638,5 +638,5 @@ Phase 3（auto-loop）：
 | `recipe-system` | LI 暴露 recipe CRUD tool 對應 |
 | `component-registry-canon` | LI `list_components` / `get_contract` 走 registry |
 | `resumable-workflow` | LI `list_paused_executions` / `resume` 用 |
-| `u6u-platform-evolution` | LI 是 evolution 之一，未來分 user-tier 時要考慮 |
+| `arcrun-platform-evolution` | LI 是 evolution 之一，未來分 user-tier 時要考慮 |
 | **mira-app** (polaris/mira) | LI 是 mira dogfood 痛點轉化的產物，roadmap 含對 mira 的回饋 |

.agents/specs/llm-interface/tasks.md

@@ -193,8 +193,8 @@
 
 ### M5.6 連動（不在本 SDD 範圍但要追蹤）
 
-- [ ] `matrix/arcrun/.agents/specs/u6u-core-mvp/` SDD 改名（另立 task，跨 SDD rename）
-- [ ] `matrix/arcrun/.agents/specs/u6u-platform-evolution/` 同上
+- [ ] `matrix/arcrun/.agents/specs/arcrun-core-mvp/` SDD 改名（另立 task，跨 SDD rename）
+- [ ] `matrix/arcrun/.agents/specs/arcrun-platform-evolution/` 同上
 - [ ] 兩個 SDD 重命名屬「u6u 品牌退場」系列，需要單獨追蹤 task
 
 ---

.claude/rules/00-sdd-protocol.md

@@ -20,8 +20,8 @@
 | Auth Recipe 系統（recipe schema、KV 格式） | `.agents/specs/arcrun/auth-recipe.md` |
 | Landing Page | `.agents/specs/arcrun/landing-page.md` |
 | CLI / SDK（Python/JS） | `.agents/specs/arcrun/sdk-and-website/` |
-| u6u-core-mvp 整體架構 | `.agents/specs/u6u-core-mvp/` |
-| u6u Platform Evolution | `.agents/specs/u6u-platform-evolution/` |
+| arcrun-core-mvp 整體架構 | `.agents/specs/arcrun-core-mvp/` |
+| Platform Evolution | `.agents/specs/arcrun-platform-evolution/` |
 | Credential 長期規格（需求源） | `docs/user_requirements/credential_parts.md` |
 
 讀 `design.md` 和 `tasks.md` 兩份。

.claude/rules/04-current-progress.md

@@ -61,9 +61,9 @@
 | Auth Recipe 系統（schema、預建 20 個服務） | `.agents/specs/arcrun/auth-recipe.md` |
 | Landing Page | `.agents/specs/arcrun/landing-page.md` |
 | SDK + Website | `.agents/specs/arcrun/sdk-and-website/design.md` |
-| arcrun MVP 整體 | `.agents/specs/u6u-core-mvp/design.md` |
+| arcrun MVP 整體 | `.agents/specs/arcrun-core-mvp/design.md` |
 | Credential 長期規格（需求源） | `docs/user_requirements/credential_parts.md` |
-| u6u Platform Evolution | `.agents/specs/u6u-platform-evolution/design.md` |
+| Platform Evolution | `.agents/specs/arcrun-platform-evolution/design.md` |
 | Tech Stack 詳細 | `.agents/steerings/tech.md` |
 
 ---

CLAUDE.md

@@ -58,8 +58,8 @@
 | Auth Recipe 系統 | `.agents/specs/arcrun/auth-recipe.md` |
 | Landing Page | `.agents/specs/arcrun/landing-page.md` |
 | SDK + Website | `.agents/specs/arcrun/sdk-and-website/` |
-| arcrun MVP 整體 | `.agents/specs/u6u-core-mvp/` |
-| u6u Platform Evolution | `.agents/specs/u6u-platform-evolution/` |
+| arcrun MVP 整體 | `.agents/specs/arcrun-core-mvp/` |
+| Platform Evolution | `.agents/specs/arcrun-platform-evolution/` |
 | Credential 長期規格（需求源） | `docs/user_requirements/credential_parts.md` |
 | Tech Stack 詳細 | `.agents/steerings/tech.md` |