feat(cohort): reconcile 500-artist telemetry, update avatars, and add drift detection

- Decouple commercial CSPC sales columns from the 500 cohort telemetry feed
- Synchronize 100% canonical platform URLs (YouTube, Spotify, Instagram) from hiffi_catalog.db to hiffi_multiplatform_500.csv
- Enforce Tier-1 zero-imputation policy for Hak (@haknyc) with RFC 8259-compliant nulls
- Reconcile and crop portrait avatar assets across cohort entities
- Implement automated drift detector and velocity circuit breaker (drift_detector.py)

scripts/resolve_missing_platform_urls.py

@@ -116,4 +116,5 @@ def main():
     conn.close()
 
 if __name__ == "__main__":
-    main()
+    main()
+