e003e4ba47
The CLOB API does not expose 24h volume or order-book liquidity, so the size_anomaly detector currently has no real ratio to compare a trade against and falls back to the niche-base 0.2 confidence floor. That makes the volume_impact / book_impact thresholds essentially dead code. This change adds a small client for the public gamma-api markets endpoint and merges its volume24hr / liquidityNum snapshot into MarketMetadata during the existing periodic sync. The detector can now compute real volume and book impact ratios. Notes on the gamma client: - gamma-api enforces a server-side max of 100 markets per page and caps `offset` around 10000. The client paginates with bounded concurrency, sorted by `volume24hr desc`, so the most-traded markets (which is where size anomalies actually matter) are always covered. Markets beyond that window have negligible recent volume and the niche path handles them fine without a ratio. - Failures are swallowed: a degraded gamma endpoint must not stop CLOB metadata from being cached, since size_anomaly + the niche path remain functional with `daily_volume=None`. MarketMetadata gains three optional Decimal fields (daily_volume, weekly_volume, liquidity); to_dict / from_dict round-trip is preserved and older cache entries without these keys deserialize cleanly. Tests: 12 new tests for GammaClient (parsing, single-page, short-page stop, offset-cap clean stop, retry, malformed responses); existing metadata_sync tests updated to inject a mocked GammaClient so they don't hit the real network. Co-authored-by: schrodinger01 <schrodinger01@users.noreply.github.com>