Tags: cloudQuant/bt_api_exmo

fix: reset CI to clean state with proper pytest installation and Wind…

…ows compatibility

chore: upgrade bt_api_exmo - code review, ruff fixes, CI/CD improvements

- Applied ruff fixes (I001, UP037)
- Fixed CI/CD workflow syntax (${} -> ${{}})
- Updated Python version matrix to 3.9-3.14
- Updated README and docs to use BtApi pattern
- Added comprehensive ruff configuration
- All tests passing (7/7)