Code quality improvements: Fix formatting and style issues

[Copilot]

This PR addresses several code quality issues identified through automated linting tools, making targeted improvements to enhance code consistency and maintainability.

Changes Made

Code Formatting Fixes

• Removed trailing whitespace in docstrings in qiskit/circuit/classical/types/__init__.py
• Fixed docstring formatting in qiskit/circuit/commutation_library.py (removed trailing space)
• Added missing trailing commas in function signatures in qiskit/circuit/controlflow/_builder_utils.py to comply with Black formatting standards

Code Style Improvements

• Replaced unnecessary dict comprehensions with more efficient dict.fromkeys() calls:
  • In qiskit/circuit/quantumcircuit.py: 3 instances where dictionaries were created with the same value for all keys
  • In qiskit/circuit/library/arithmetic/polynomial_pauli_rotations.py: 1 instance for rotation coefficients initialization

API Improvements

• Added __version__ to __all__ in qiskit/__init__.py to properly expose the version attribute in the public API

Example of Changes

Before:

starts = {q: 0 for q in qubits}
dones = {q: False for q in qubits}

After:

starts = dict.fromkeys(qubits, 0)
dones = dict.fromkeys(qubits, False)

Verification

All changes have been verified through:

• Automated linting tools (Black, Ruff) showing no remaining issues for the addressed code
• Functional testing confirming that core Qiskit functionality remains intact
• Import testing ensuring all modified modules work correctly

These improvements follow the project's coding standards and make the codebase more maintainable without affecting functionality.

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