🎨 Palette: Add helpful tooltips to financial settings

[aarjava]

💡 What: Added explanatory tooltips to "High Volatility Quantile", "Transaction Cost (bps)", and "Allow Short Selling" inputs in the sidebar. Also added matplotlib dependency to prevent dashboard crash.
🎯 Why: Financial jargon like "bps" and "quantiles" can be confusing for non-expert users. Tooltips provide immediate context and concrete examples (e.g., "10 bps = 0.10%").
♿ Accessibility: Reduces cognitive load by providing definitions in context.

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PR created automatically by Jules for task 2755689793335810403 started by @aarjava

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