🎨 Palette: Add tooltips to financial inputs & fix runtime crash

[aarjava]

💡 What: Added help tooltips to Transaction Cost, Factor Beta Window, Regime Vol Window, and ADV Participation % inputs in the sidebar. Also added matplotlib to requirements.txt to fix a pandas.style.background_gradient crash.
🎯 Why: Clarify technical financial terms (basis points, adv participation) for users and fix a critical runtime error observed in the dashboard.
📸 Before/After: Inputs now show a question mark icon with explanatory text on hover. The dashboard no longer shows an ImportError in the main view.
♿ Accessibility: Tooltips provide context for screen readers and visual users alike.

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PR created automatically by Jules for task 5488744237898539841 started by @aarjava

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