feat: introduce ruff for linting and code quality

This commit migrates the project from pylint/pycodestyle to ruff for linting,
establishing a modern Python development standard with automated code quality checks.

- Created pyproject.toml with comprehensive ruff configuration:
  - Line length: 100 characters
  - Target Python: 3.8+
  - Enabled rules: E, W, F, I (isort), C4, B, UP
  - Configured isort to recognize Adyen as first-party module
  - Added dev dependencies for ruff and pre-commit

- Created .pre-commit-config.yaml:
  - Set up ruff-lint hook with auto-fix enabled
  - Set up ruff-format hook for code formatting

- Updated Makefile:
  - Replaced pylint/pycodestyle with ruff in install target
  - Added 'lint' target: ruff check Adyen test
  - Added 'lint-fix' target: ruff check --fix Adyen test
  - Added 'format' target: ruff format Adyen test

- Updated tox.ini:
  - Added 'lint' environment for CI linting checks
  - Configured lint environment to run ruff checks

- Updated setup.py:
  - Added 'dev' extras with ruff and pre-commit dependencies

- Fixed 301 linting issues (reduced from 301 to 0):
  * 111 f-string without placeholders (F541) - Removed extraneous f prefixes
  * 102 super() call with parameters (UP008) - Updated to modern super() syntax
  * 30 unsorted imports (I001) - Sorted imports correctly
  * 26 unused imports (F401) - Added explicit re-exports for public API
  * 11 unused variables (F841) - Added proper response assertions to tests
  * 4 printf-style formatting (UP031) - Converted to f-strings
  * Other minor issues: blank lines, future imports, mock imports, trailing whitespace

- Enhanced tests with proper response assertions:
  - DisputesTest: Verify disputeServiceResult and defenseReasons structure
  - StoredValueTest: Assert resultCode == 'Success' and pspReference
  - TransfersTest: Verify transfer response fields and status
  - UtilTest: Assert paymentMethods structure and content

- Unified linting toolchain with ruff
- Faster linting (ruff is 10-100x faster than pylint)
- Better code consistency across the project
- Pre-commit hooks for automatic quality checks before commits
- Comprehensive test coverage with response validation
- Modern Python practices (f-strings, updated syntax)

1. Install dev dependencies: pip install -e '.[dev]'
2. Install pre-commit hooks: pre-commit install
3. Run linting: make lint
4. Fix linting issues: make lint-fix
5. Format code: make format
6. Run tests: make tests or tox

ci: add github actions workflow for linting

- Added lint job to run ruff check and ruff format on Python 3.8-3.12
- Added pre-commit job using pre-commit/action
- Runs on push to main/develop and on pull requests
- Includes pip caching to speed up workflow execution

ci: expand python version matrix to 3.8-3.14

- Updated lint job to test all supported Python versions
- Matches tox.ini and setup.py configuration
- Now covers Python 3.13 and 3.14

style: apply ruff formatting to all source files

- Formatted 116 files with ruff formatter
- Ensures consistent code style across the project
- Fixes CI formatting check failures