Optimize Python CSV Processor

I already have a working Python script that processes structured text—mainly CSV and the occasional JSON file—and I need a clean, reliable revision. The current version runs, but it is slow on large datasets and throws intermittent parsing errors when field counts vary.

Here’s what I need from you:

• Review and refactor the existing .py code for clarity, speed, and robustness.
• Ensure all parsing logic gracefully handles edge-cases like empty lines, malformed rows, and unexpected encodings.
• Add concise logging (built-in logging module is fine) so I can trace each processing stage without drowning in messages.
• Provide unit tests covering the main data-processing functions; I use pytest.
• Package the final script as a Windows-friendly executable (PyInstaller or similar) alongside the plain .py version.

I will supply the current script, sample CSV/JSON files, and a quick performance benchmark. Deliver back the updated source, test suite, and compiled exe, along with a short “how to run” note. If you are comfortable profiling Python and squeezing extra speed out of text processing, this should be a straightforward win for both of us.