Initial commit: Logo detection test framework

Add DETR+CLIP based logo detection library and test framework:
- DetectLogosDETR class for logo detection and matching
- Test script with margin-based and multi-ref matching methods
- Data preparation script for test database
- Documentation for API usage and test methodology

.gitignore

@@ -0,0 +1,38 @@
+# Python-generated files
+__pycache__/
+*.py[oc]
+build/
+dist/
+wheels/
+*.egg-info
+
+# Virtual environments
+.venv
+
+# Image directories
+reference_logos/
+test_images/
+
+# Image files
+*.jpg
+*.jpeg
+*.png
+*.gif
+*.bmp
+*.webp
+
+# Database and data files
+*.db
+*.json
+*.pkl
+
+# Cache files
+.embedding_cache.pkl
+
+# IDE
+.idea/
+.vscode/
+
+# Results files
+results*.txt
+sample_results.txt