⚡ Bolt: optimize ticker discovery hot paths

[toreleon]

💡 What: Refactored the rsi14 and volume aggregation logic in src/tools/discover.ts to use direct for loops instead of chaining array methods like .map(), .slice(), and .reduce().
🎯 Why: The buildCandidate function is a hot path used to evaluate the entire ticker universe. Creating intermediate arrays for every candidate adds unnecessary garbage collection and memory allocation overhead.
📊 Impact: Reduces memory allocations per candidate, improving the overall speed of the ticker discovery tool.
🔬 Measurement: Verified by running pnpm test and pnpm typecheck to ensure the mathematical outputs are identical and that the changes correctly handle out-of-bounds cases gracefully, matching the original .slice() behavior.

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PR created automatically by Jules for task 12445644334209806449 started by @toreleon

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