⚡ Bolt: Replace O(n) array filtering with O(log n) binary search

[toreleon]

💡 What: Added a reusable findLastBarIndex binary search utility to src/data/sources/dnsePublic.ts and updated hot-path time-series data truncation in clipBars, vnindexAt, and priceOverride to use it.
🎯 Why: Time-series arrays (like OHLCV bars) are chronologically sorted. Using Array.prototype.filter to look up data up to a specific time point runs in O(n) time, creating significant performance overhead in tight loops like the backtesting engine.
📊 Impact: Reduces lookahead overhead from O(n) to O(log n) per lookup. For long backtest runs processing large OHLCV arrays on every 30m turn, this substantially speeds up the data truncation step, directly speeding up loop execution.
🔬 Measurement: All tests pass normally. Lookups on larger bars datasets will show marked reduction in CPU cycle time due to the O(log n) approach versus processing every element.

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PR created automatically by Jules for task 7501572209619970543 started by @toreleon

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