fix: Enforce min_chunk_size in RAG chunker

- Filter out chunks smaller than min_chunk_size (default 100 tokens)
- Exception: Keep all chunks if entire document is smaller than target size
- All 15 tests passing (100% pass rate)

Fixes edge case where very small chunks (e.g., 'Short.' = 6 chars) were
being created despite min_chunk_size=100 setting.

Test: pytest tests/test_rag_chunker.py -v

.dockerignore

@@ -0,0 +1,83 @@
+# Python artifacts
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Virtual environments
+venv/
+env/
+ENV/
+.venv
+
+# Testing
+.pytest_cache/
+.coverage
+.coverage.*
+htmlcov/
+.tox/
+.hypothesis/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.DS_Store
+
+# Git
+.git/
+.gitignore
+.gitattributes
+
+# Documentation
+docs/
+*.md
+!README.md
+
+# CI/CD
+.github/
+.gitlab-ci.yml
+.travis.yml
+
+# Output directories
+output/
+data/
+*.zip
+*.tar.gz
+
+# Logs
+*.log
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+
+# Environment files
+.env
+.env.*
+!.env.example
+
+# Test files
+tests/
+test_*.py
+*_test.py
+
+# Docker
+Dockerfile*
+docker-compose*.yml
+.dockerignore