fix(miners): use API successMultiplier in score composite footer

[Yurii214]

Summary

• Use the API-provided successMultiplier when composing the miner score-factors footer total instead of recomputing (successRate30d × credibilityRamp)³ client-side.
• Align the footer formula label with what is actually multiplied (success = successMultiplier from /score-factors).

Problem

ScoreFactorsStrip footer ("share of pool captured this round") multiplied crown, capacity, and volume factors against a client-derived (successRate30d × credibilityRamp)³ term.

The /miners/:hotkey/score-factors response already includes successMultiplier (the canonical success term computed server-side), but the UI never used it. This left the footer value vulnerable to drift from backend scoring logic and contradicted the stale inline formula note.

Changes

• src/components/miners/ScoreFactorsStrip.tsx
  • composeMultiplier: sf.successMultiplier replaces (sf.successRate30d * sf.credibilityRamp) ** 3
  • Footer annotation updated to = crown × cap × vol × success

Why this is safe

• Uses an existing typed field already returned by the same endpoint.
• Keeps all card-level displays unchanged (Success rate and Credibility cards still render their own fields as before).
• Narrows client logic and avoids duplicating backend scoring math.

Test plan

• npm run lint
• npm run build
• Manual sanity check on /miners/:hotkey: footer value tracks crownShareWindow × capacityFactor × volumeFactor × successMultiplier (rounded display)

Made with Cursor

[Yurii214]

Why this is safe

• Single-field swap: composeMultiplier now uses successMultiplier from the same /score-factors payload that already feeds the five factor cards — no new API surface or client-side scoring logic.
• Scoped change: One file, footer composite only. Success rate and Credibility cards still render successRate30d / credibilityRamp unchanged.
• Fixes known drift: The removed client formula (successRate30d × credibilityRamp)³ contradicted the stale TODO and could disagree with server scoring (e.g. credibility timeout zeroing from feat(miners): show credibility auto-zeroed on excess timeouts #111).
• Build verified: npm run lint and npm run build pass on this branch.

@anderdc @LandynDev — ready for review when you have a moment. Thanks!