🎨 Palette: Enhanced CLI UX and fixed accessibility crash

[EiJackGH]

💡 What:

• Refactored Colors class to fix a crash when using --no-color and remove duplicate code.
• Added input validation for CLI arguments (days, cash, price) with friendly error messages.
• Enhanced the final simulation report with ROI %, Total Trades count, and ASCII box formatting.
• Fixed a bug where the 'Daily Trading Ledger' header was printed twice.

🎯 Why:

• Users need to be able to run the tool without colors for accessibility or logging purposes (--no-color was broken).
• Users need to know if they provide invalid inputs (e.g. negative days) instead of seeing a stack trace.
• The final report lacked key metrics like ROI and trade volume, which are essential for evaluating a trading strategy.

📸 Before/After:
Before:

• Crash on --no-color.
• Double header print.
• Basic text output.

After:

• Clean, crash-free execution with --no-color.
• Single, conditional header.
• Rich, boxed final report with ROI and trade stats.

♿ Accessibility:

• Fixed the --no-color flag to correctly disable ANSI codes.

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PR created automatically by Jules for task 15874837156841492643 started by @EiJackGH

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