Add OTLP metric ingestion pipeline that persists Sum/Histogram/Gauge
data points to fabric.db with canonical instrument names:
- MetricAccumulator in workerAnalytics.ts accumulates per-worker
running totals for tokens, cost, durations, bead counts
- Schema v2 in historicalStore.ts adds metric_samples and
session_worker_summaries tables with source preference tracking
- flushMetricSamples() in store.ts drains accumulator → SQLite on
every event, upserting session summaries and live session rows
- docs/schema.md documents instrument names and resolution order
Fix source preference ordering (otlp-metric > otlp-span > log-derived)
using CASE-based SQL sort instead of alphabetical ASC which was
inverted. Fix metricsSource detection to not require costUsd > 0.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Add NeedleEvent interface as the canonical internal shape versioned at
schema-version 1. Parser validates wire format and asserts schema version
on incoming events. Legacy LogEvent retained as backward-compatible adapter.
docs/schema.md documents all fields, the (worker_id, sequence) ordering
contract, and the full event taxonomy cross-referenced with NeedleEventType.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
