signalkit-core

The engine behind trendkit, extracted so any counter can be tracked, stored, and scored:

• Subjects/observations: one append-only snapshot model ((kind, key) identity, immutable readings).
• Velocity: Δscore/day clamped to a one-hour minimum window — single-snapshot subjects report zero rather than a fabricated spike.
• Deterministic time: timestamps flow through an injected [clock_kit::Clock] (MockClock in tests).
• Source trait: async collectors write via a shared CollectCtx; the future is deliberately !Send (sequential pacing by design, SQLite confined to the collecting task).

Integrity analysis (fork-ratio verdicts, org-burst detection, velocity outliers) lives in signalkit-integrity.