chore:migrate form black to ruff(#916)

[sun-9545sunoj]

This PR transitions the qsim repository from Black to Ruff. This consolidates formatting, linting, and import sorting into a single, high-performance tool, aligning qsim with the standards used in related projects like Cirq.

Main Changes
Configuration:
Updated pyproject.toml to remove [tool.black] and [tool.isort] configurations.

Added [tool.ruff] targeting Python 3.10, including specific isort settings (combine-as-imports, known-first-party).

Development Environment:

Swapped black for ruff in dependencies.

Updated .pre-commit-config.yaml to use Ruff hooks.

Scripts & Automation:

Refactored check/format-incremental to utilize ruff check --fix and ruff format.

CI/CD & UX:

Replaced the legacy black.json problem matcher with a new ruff.json matcher.

Updated .github/workflows/ci.yaml to register the Ruff matcher, ensuring linting errors are annotated directly in the GitHub PR UI.

Verification Performed
Linting/Formatting: Ran check/format-incremental locally; the codebase is now 100% Ruff-compliant.

Package Integrity: Successfully ran python -m pytest --collect-only.

Result: 102 tests collected. This confirms that the reformatting and import sorting did not introduce syntax errors or break the package structure.

CI Logic: Verified the regex in ruff.json matches the output format of the astral-sh/ruff-action.

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[gemini-code-assist]

Code Review

This pull request migrates the project from Black and isort to Ruff, consolidating linting and formatting. No security vulnerabilities were found. However, a critical issue was identified in the check/format-incremental script where a variable is used without being defined. Additionally, there's a potential regression in the isort configuration within pyproject.toml and a minor style guide violation in the new ruff.json problem matcher. Please refer to the detailed comments for specific suggestions.

[gemini-code-assist]

The arg_color variable is used in the ruff commands on lines 118 and 137, but it is no longer defined in the script. The block of code that defined it was removed as part of this change. This will likely cause the script to fail or not produce colored output as intended. The definition should be restored.

# Color the output if it goes to a terminal or GitHub Actions log.
arg_color=()
if [[ -t 1 || "${CI}" == true ]]; then
    arg_color=("--color")
fi

# Run ruff for import sorting.
# We do this first so that if it changes files, the formatting step will pick them up.
echo "Running ruff check (isort)..."
check_args=("check" "--select" "I" "${arg_color[@]}")

[gemini-code-assist]

The file is missing a final newline. The repository style guide requires files to end with a newline.

Suggested change

	}
	}

References

1. Files must end with a final newline, unless they are special files that do not normally have ending newlines. ^(link)