Fix: naming and exception messages cleanup

[niko-zvt]

Summary

Code quality and consistency improvements: naming fixes and correct function names in exception messages.

Changes

• Launcher: Rename handles_skip_warnings → handle_skip_warnings to match other command handlers (handle_pause, handle_colors, etc.).
• BaseFile (Default & Windows): Use "BaseFile::rename()" in FileException messages inside BaseFile::rename() instead of "RawFile::rename()"; add short comment explaining the choice.
• ConvertInteger.h: Build negative result in tostr_si_commas with out += instead of return std::string("-") + ... to match file style.

Testing

• Build Launcher and DigitViewer2.
• No behavior change; comments and exception text only where applicable.

[niko-zvt]

@Mysticial Hi! Thanks for the amazing y-crunch project - it’s truly impressive. I’ve submitted a small PR to help with some code adjustments. Hope it’s useful