⚡ Bolt: Optimize array allocations in ticker discovery

[toreleon]

💡 What: Replaced O(N) .map(), .slice(), and .reduce() calls with in-place indexed for loops in buildCandidate and rsi14 functions within src/tools/discover.ts.
🎯 Why: To reduce unnecessary memory allocations and garbage collection overhead during the frequently executed ticker discovery process (which processes up to 12 candidates concurrently out of hundreds of tickers).
📊 Impact: Expected to reduce memory footprint and garbage collection pauses, making the candidate discovery process faster and more stable when filtering large stock universes.
🔬 Measurement: Run pnpm test tests/discover.test.ts to verify the functionality remains identical. Profiling the discoverTickers function will show reduced object allocation counts.

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PR created automatically by Jules for task 11773082166246151397 started by @toreleon

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