Implement plain KNN classifier and testing infrastructure

- Add plain KNN implementation with JSONL data processing
- Create Docker deployment setup with python:3.13-slim base
- Add comprehensive OJ-style testing system with accuracy validation
- Update README with detailed scoring mechanism explanation
- Add run.sh script following competition manual requirements

🤖 Generated with [Claude Code](https://claude.ai/code)

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

dataset/answer.jsonl

@@ -0,0 +1 @@
+{"answer":[93,94,90,27,87,50,47,16,6,40]}