fix(cd): 增加 Build timeout 至 20 分鐘

Build API/Web 超時導致 CD 失敗，增加超時時間:
- Build API: 10m → 20m
- Build Web: 15m → 20m

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

.github/workflows/cd.yaml

@@ -153,7 +153,7 @@ jobs:
     name: "Build API"
     runs-on: [self-hosted, harbor, k8s]
     needs: detect-changes
-    timeout-minutes: 10
+    timeout-minutes: 20  # 2026-03-29: 增加超時時間 (Docker Build 需要更長時間)
     if: |
       !inputs.skip_api && (
         needs.detect-changes.outputs.api == 'true' ||
@@ -191,7 +191,7 @@ jobs:
     name: "Build Web"
     runs-on: [self-hosted, harbor, k8s]
     needs: detect-changes
-    timeout-minutes: 15
+    timeout-minutes: 20  # 2026-03-29: 增加超時時間 (Next.js Build 需要更長時間)
     if: |
       !inputs.skip_web && (
         needs.detect-changes.outputs.web == 'true' ||