Replace Pylint with Ruff, fix lint issues, and expand CI matrix

[hyperfinitism]

Summary

• Revise README.md summary and resolve Markdown lint warnings
• Resolve Ruff lint errors across source, examples, and tests (deprecated typing imports, import sorting, unnecessary mode args, formatting)
• Replace Pylint with Ruff as the project's linter/formatter — delete .pylintrc and pylint.yml, add ruff.yml workflow and [tool.ruff] config in pyproject.toml
• Expand pytest CI matrix to run on Python 3.10 and 3.11 in addition to 3.12

Changes

docs: Revise summary and resolve lint warnings

• README.md: Updated project description, fixed Markdown lint warnings

chore: Resolve Ruff lint errors

• imapcrutils/libs.py: Replace typing.List/Tuple/Callable with collections.abc.Callable + builtin list/tuple
• examples/pcr10.py, examples/boot_aggregate.py: Fix import sort, remove unnecessary 'r' mode arg
• tests/: Fix import sort, formatting
• imapcrutils/__init__.py: Remove # flake8: noqa comment

ci: Replace Pylint with Ruff

• Delete .pylintrc, .github/workflows/pylint.yml
• Add .github/workflows/ruff.yml (ruff check + ruff format --check)
• Add [tool.ruff] config to pyproject.toml (line-length=128, target-version=py310, selected rule sets: E/W/F/I/UP/B/SIM/PLR/PLW/PLE)
• Replace pylint with ruff in [project.optional-dependencies]

ci: Enable pytest for Python 3.10 and 3.11

• .github/workflows/pytest.yml: Expand matrix to ["3.10", "3.11", "3.12"]

Test plan

• Ruff CI workflow passes (ruff check + ruff format --check)
• Pytest CI workflow passes on Python 3.10, 3.11, and 3.12