refactor(ai): 模組化重構 - NVIDIA chat 移至 NvidiaProvider

符合 feedback_lewooogo_modular_enforcement.md 規範:
- 移除 openclaw.py 中的 _call_nvidia() (重複邏輯)
- 新增 NvidiaProvider.chat() 方法
- 更新 INvidiaProvider Protocol
- openclaw.py 改用 get_nvidia_provider().chat()
- 測試移至 test_nvidia_chat.py

架構層次:
- Router → Service → Provider (正確)
- 禁止 Service 層重複實作已存在的 Provider 功能

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

.github/workflows/nightly-llm.yaml

@@ -1,96 +0,0 @@
-# =============================================================================
-# AWOOOI Nightly LLM Tests (2026-03-26)
-# =============================================================================
-# 🤖 完整 LLM 測試 - 每日執行 (CPU 推理需 ~45 分鐘)
-#
-# 測試內容:
-# - test_model_regression.py: 模型回歸測試 (4 案例)
-# - test_prompt_validation.py: Prompt 品質驗證 (5 案例)
-#
-# 觸發時機:
-# - 每日 00:00 UTC (08:00 台北)
-# - 手動觸發
-
-name: Nightly LLM Tests
-
-on:
-  schedule:
-    - cron: '0 0 * * *'  # 每日 00:00 UTC (08:00 台北)
-  workflow_dispatch:
-    inputs:
-      timeout:
-        description: 'Timeout per test (seconds)'
-        required: false
-        default: '300'
-
-concurrency:
-  group: nightly-llm
-  cancel-in-progress: true
-
-env:
-  PYTHON_VERSION: '3.11'
-  OLLAMA_URL: http://192.168.0.188:11434
-  OLLAMA_MODEL: qwen2.5:7b-instruct
-
-jobs:
-  llm-regression:
-    name: LLM Regression Tests
-    runs-on: [self-hosted, harbor, k8s]
-    timeout-minutes: 60  # 1 小時超時
-    steps:
-      # 2026-03-29 Claude Code: 修復 _diag/pages 檔案衝突
-      - name: "Clean Runner Diagnostics"
-        run: |
-          RUNNER_ROOT=$(dirname "$(dirname "$RUNNER_TEMP")")
-          rm -rf "$RUNNER_ROOT/_diag/pages" 2>/dev/null || true
-          mkdir -p "$RUNNER_ROOT/_diag/pages" 2>/dev/null || true
-
-      - uses: actions/checkout@v4
-
-      - name: Setup Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-
-      - name: Install uv
-        uses: astral-sh/setup-uv@v3
-
-      - name: Check Ollama
-        run: |
-          echo "🔗 檢查 Ollama 服務..."
-          if curl -s --connect-timeout 10 ${{ env.OLLAMA_URL }}/api/tags > /dev/null; then
-            echo "✅ Ollama 可用"
-            curl -s ${{ env.OLLAMA_URL }}/api/tags | python3 -c "import sys,json; [print(f'  - {m[\"name\"]}') for m in json.load(sys.stdin).get('models',[])]"
-          else
-            echo "❌ Ollama 無法連線"
-            exit 1
-          fi
-
-      - name: Model Regression Tests
-        working-directory: apps/api
-        env:
-          PYTHONPATH: ${{ github.workspace }}/apps/api
-        run: |
-          echo "🧪 執行模型回歸測試..."
-          echo "   CPU 模式: 預估 ~15-20 分鐘"
-          uv sync
-          uv run pytest tests/test_model_regression.py -v --tb=short \
-            --timeout=${{ github.event.inputs.timeout || '300' }}
-
-      - name: Prompt Validation Tests
-        working-directory: apps/api
-        env:
-          PYTHONPATH: ${{ github.workspace }}/apps/api
-        run: |
-          echo "📝 執行 Prompt 品質驗證..."
-          echo "   CPU 模式: 預估 ~20-25 分鐘"
-          uv run pytest tests/test_prompt_validation.py -v --tb=short \
-            --timeout=${{ github.event.inputs.timeout || '300' }}
-
-      - name: Summary
-        if: always()
-        run: |
-          echo "📊 Nightly LLM 測試完成"
-          echo "   Ollama: ${{ env.OLLAMA_URL }}"
-          echo "   Model: ${{ env.OLLAMA_MODEL }}"
-          echo "   Mode: CPU (no GPU)"