Fix Chinese font rendering in all chart outputs

- Add src/font_config.py: centralized font detection that auto-selects
  from Noto Sans SC > Hiragino Sans GB > STHeiti > Arial Unicode MS
- Replace hardcoded font lists in all 18 modules with unified config
- Add .gitignore for __pycache__, .DS_Store, venv, etc.
- Regenerate all 70 charts with correct Chinese rendering

Previously, 7 modules (fft, wavelet, acf, fractal, hurst, indicators,
patterns) had no Chinese font config at all, causing □□□ rendering.
The remaining 11 modules used a hardcoded fallback list that didn't
prioritize the best available system font.

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

src/anomaly.py

@@ -705,9 +705,8 @@ def run_anomaly_analysis(
     print(f"数据范围: {df.index.min()} ~ {df.index.max()}")
     print(f"样本数量: {len(df)}")
 
-    # 设置中文字体
-    plt.rcParams['font.sans-serif'] = ['Arial Unicode MS', 'SimHei', 'DejaVu Sans']
-    plt.rcParams['axes.unicode_minus'] = False
+    from src.font_config import configure_chinese_font
+    configure_chinese_font()
 
     # --- 集成异常检测 ---
     print("\n>>> [1/5] 执行集成异常检测...")