#14 Make C++ comment stripping safe for string and raw string literals

[iray-tno]

Summary

• Replace regex-only C++ comment removal with a small scanner that preserves normal string literals, char literals, and raw string literals.
• Use the scanner in both C++ preprocessing and C++ minification.
• Add regression tests for URLs, block-comment markers in strings, char literals, raw strings, and minifier behavior.

Tests

• uv run pytest tests/test_cpp_preprocessor.py -q
• uv run pytest tests/test_cpp_integration.py tests/test_error_messages.py -q
• uv run pytest -q

Closes #14.