[ShahadatTest]

Description

Closes #111.

Add --no-split to run without splitting when --splits and --group are configured in pytest's addopts. When splitting is disabled, skip split-specific group/count validation and leave the splitting plugin unregistered. Duration recording and other pytest selection options remain available.

Nine regression cases cover both algorithms, absent/incomplete/out-of-range split configuration, -k selection, and storing durations for the full suite. All nine fail against the original production code because the option is not recognized. README usage and the unreleased changelog are updated.

Validation on Windows:

• CPython 3.12.10 / pytest 9.1.1: 90 passed.
• CPython 3.10.20 / pytest 6.2.5: 90 passed.
• Both full runs meet the configured 90% coverage threshold (90.65%). They emit a coverage module-import warning; pytest 6 also emits a pluggy teardown warning in the existing invalid-algorithm usage-error test.
• Applicable pre-commit hooks pass, including Ruff, mypy, and changelog verification, using the versions in poetry.lock. git diff --check passes. The editable installs use poetry-core 2.2.1 because 2.5.0 generates a dependency specifier that uv rejects for the existing pytest version union.

Prepared with assistance from OpenAI Codex; the change and validation were performed by the agent.

Checklist

• Tests covering the new functionality have been added
• Documentation has been updated OR the changes are too minor to be documented
• The Changes are listed in the CHANGELOG.md OR the changes are insignificant