fix(runner): v3 - 只清理 _diag/pages，不碰 RUNNER_TEMP

根因分析:
- RUNNER_TEMP 在同一 Runner 的所有 Jobs 之間共享
- 清理 RUNNER_TEMP 會刪除其他 Job 的 _runner_file_commands
- 導致 "Missing file at path: _runner_file_commands/set_output_xxx"

修正:
- 移除所有 RUNNER_TEMP 清理邏輯
- 只清理 _diag/pages (這是唯一需要清理的目錄)
- 簡化清理腳本，移除不必要的複雜度

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/cd.yaml

@@ -57,51 +57,23 @@ jobs:
     timeout-minutes: 1
     steps:
       # =======================================================================
-      # 2026-03-29: Runner _diag/pages 檔案衝突永久修復
-      # 問題: 並行 Job 寫入同一診斷檔案導致 "file already exists"
-      # 解法: 強制清理 + flock 鎖定 + 重建目錄
+      # 2026-03-29: Runner _diag/pages 檔案衝突修復 (v3)
+      # 重要: 只清理 _diag/pages，不碰 RUNNER_TEMP
+      # 原因: RUNNER_TEMP 在所有 Jobs 之間共享，清理會破壞其他 Job
       # =======================================================================
-      - name: "Clean Runner Diagnostics (Anti-Collision)"
+      - name: "Clean Runner Diagnostics"
         run: |
-          set +e  # 不因清理失敗而中斷
-
           RUNNER_ROOT=$(dirname "$(dirname "$RUNNER_TEMP")")
-          DIAG_DIR="$RUNNER_ROOT/_diag"
-          PAGES_DIR="$DIAG_DIR/pages"
-          LOCK_FILE="/tmp/runner-diag-cleanup.lock"
+          PAGES_DIR="$RUNNER_ROOT/_diag/pages"
 
-          echo "🧹 Cleaning Runner diagnostics..."
-          echo "   RUNNER_ROOT: $RUNNER_ROOT"
-          echo "   PAGES_DIR: $PAGES_DIR"
+          # 只清理 _diag/pages (唯一需要清理的目錄)
+          rm -rf "$PAGES_DIR" 2>/dev/null || true
+          mkdir -p "$PAGES_DIR" 2>/dev/null || true
 
-          # 使用 flock 確保同一時間只有一個清理程序
-          (
-            flock -w 10 200 || { echo "⚠️ Lock timeout, proceeding anyway"; }
+          # 清理 Claude worktrees (本地專案目錄)
+          rm -rf .claude/worktrees 2>/dev/null || true
 
-            # 1. 清理 _diag/pages (最關鍵)
-            if [ -d "$PAGES_DIR" ]; then
-              # 刪除所有 .log 檔案
-              find "$PAGES_DIR" -name "*.log" -type f -delete 2>/dev/null
-              # 重建目錄確保乾淨
-              rm -rf "$PAGES_DIR" 2>/dev/null
-              mkdir -p "$PAGES_DIR" 2>/dev/null
-              echo "   ✅ Cleaned _diag/pages"
-            fi
-
-            # 2. 清理 RUNNER_TEMP (排除 _runner_file_commands)
-            # 注意: 不能刪除整個目錄，否則會破壞 Runner 內部通訊
-            find "$RUNNER_TEMP" -mindepth 1 -maxdepth 1 ! -name "_runner_file_commands" -exec rm -rf {} \; 2>/dev/null || true
-            echo "   ✅ Cleaned RUNNER_TEMP (preserved _runner_file_commands)"
-
-            # 3. 清理 Claude worktrees
-            rm -rf .claude/worktrees 2>/dev/null
-
-            # 4. 清理陳舊的 _work 暫存
-            find "$RUNNER_ROOT/_work" -name "*.tmp" -mmin +30 -delete 2>/dev/null || true
-
-          ) 200>"$LOCK_FILE"
-
-          echo "✅ Runner cleanup completed"
+          echo "✅ Cleaned _diag/pages"
 
       # =======================================================================
       # ADR-035: Telegram 告警鏈路強制驗證