🎨 Palette: Add concrete examples to statistical and financial parameter tooltips

[aarjava]

💡 What: Added help tooltips with concrete examples to complex financial input widgets in src/dashboard.py (e.g., bt_cost, adv_pct, vol_window). Also created .Jules/palette.md to document this learning.
🎯 Why: Adding concrete examples to statistical and financial parameters (like basis points or volatility quantiles) significantly reduces user cognitive load and clarifies abstract inputs.
♿ Accessibility: Improves usability by clarifying technical terms natively via Streamlit's tooltip mechanism.

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PR created automatically by Jules for task 975481257910452629 started by @aarjava

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