perf: reduce stochastic signal window scans

[Godel-Smith]

Summary

Reduces extra rolling-window scans in stochastic_signal. The function only uses the trailing d_period %K values to compute %D, so this PR computes those trailing windows directly instead of scanning k_period windows and discarding most of them.

If this ranks for payout, I can provide payment details privately after acceptance.

Type

• Bug fix
• New strategy
• New feature
• Refactor
• Documentation
• Tests
• Chore / dependency update

Related Issue

Refs #2

Changes

• Avoids computing unused %K windows inside stochastic_signal.
• Preserves previous %K/%D output for the default d_period <= k_period path.
• Preserves the existing fallback behavior when d_period > k_period.
• Adds a focused regression test for both cases.

Benchmark

Synthetic 1000-candle input, best of 5 repeats, run with direct file import to avoid pulling app dependencies:

• k_period=14, d_period=3: old 0.508540s, new 0.150167s for 10,000 calls: 3.39x speedup
• k_period=120, d_period=3: old 4.531116s, new 0.154038s for 2,000 calls: 29.42x speedup
• Output equality check passed for both benchmark cases.

Testing

• pytest tests/ passes locally
• New tests added for new code
• Manually tested (describe how):
  • Focused local verification command passed
  • git diff --cached --check
  • benchmark script described above

Not run:

• Full pytest tests/ because this repo ignores tests/ as private/internal and the local environment does not have the full app dependency stack installed.

Checklist

• No secrets, API keys, or private keys committed
• Type hints on all new public functions
• docs/connections/service-map.md updated (if adding a new call path)
• docs/architecture/data-model.md updated (if changing DB schema)
• New strategy registered in app/strategies/signals.py (if adding a strategy)
• New strategy added to strategy index in app/onchain_logger.py (if adding a strategy)
• Breaking changes documented in PR description

Screenshots (if UI change)

N/A

[vercel]

@Godel-Smith is attempting to deploy a commit to the dragoon4002's projects Team on Vercel.

A member of the Team first needs to authorize it.