Fingerprint-snapshot foundation + strategy-drift calculator (#3/#5 groundwork)
TraderAnalytics is one row per trader, overwritten every recalculation, so there
is no history to detect strategy drift (#3) or edge fade (#5) against. Add the
missing time series:
- TraderFingerprintSnapshot entity (score, category concentration, conviction,
P50/P90 sizing, hold duration, trades/week, category-mix JSON, trait-set JSON)
+ migration AddFingerprintSnapshots (indexed by TraderId, CapturedAt).
- FingerprintSnapshotService (Infrastructure): CaptureDueAsync snapshots every
copy-relevant trader (CopytradingScore >= 40) at most ~once/day; wired into
ScoringAndAlertsWorker. GetDriftAsync reads latest-vs-baseline drift.
- FingerprintDriftCalculator (pure, Application): flags score drop, concentration
shift, sizing jump, conviction sign-flip, category-mix TVD, trait-set change.
- GET /api/traders/{id}/fingerprint-drift?baselineDays=14 read endpoint.
- Tests: drift calculator (4 scenarios) + capture service (copy-relevance,
throttle, drift read).
This is the shared foundation both #3 (drift alarm) and #5 (edge freshness) build on.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
@
Richard
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