add Python performance benchmark pipeline via PyPy

- Create specialized GitHub Action workflow for Python iterator benchmarking.
- Configure PyPy 3.10 environment to validate Position Pro algorithm efficiency.
- Decouple Python performance tracking from existing C++ infrastructure.
- Standardized Markdown table output for performance trend visualization (N=10..12).

Author: Yusheng-Hu

.github/workflows/python_bench.yml

@@ -0,0 +1,27 @@
+name: Python Iter Performance Bench
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  python-bench:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout Repository
+      uses: actions/checkout@v4
+
+    - name: Set up PyPy 3.10
+      uses: actions/setup-python@v5
+      with:
+        python-version: 'pypy-3.10'
+
+    - name: Run PP Iter Benchmark
+      run: |
+        echo "### 🐍 Position Pro Iterator Performance (PyPy)" >> $GITHUB_STEP_SUMMARY
+        echo "Comparing Python Implementation vs. C-based itertools" >> $GITHUB_STEP_SUMMARY
+        # 假设文件在 python 子目录下
+        cd python
+        python pp_iter.py >> $GITHUB_STEP_SUMMARY