v9.5: 實作標籤完全不重疊算法

- 新增 _calculate_lane_conflicts_v2() 分開返回標籤重疊和線穿框分數
- 修改泳道選擇算法，優先選擇無標籤重疊的泳道
- 兩階段搜尋：優先側別無可用泳道則嘗試另一側
- 增強日誌輸出，顯示標籤範圍和詳細衝突分數

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>

requirements-core.txt

@@ -0,0 +1,18 @@
+# TimeLine Designer - Core Dependencies (Python 3.13 compatible)
+
+# Web Framework
+fastapi==0.115.6
+uvicorn[standard]==0.34.0
+python-multipart==0.0.20
+
+# Data Validation
+pydantic==2.10.5
+pydantic-settings==2.7.1
+
+# Testing
+pytest==8.3.4
+pytest-asyncio==0.25.2
+pytest-cov==6.0.0
+
+# Utilities
+python-dateutil==2.9.0.post0