initial: import DOLPHIN baseline 2026-04-21 from dolphinng5_predict working tree

Includes core prod + GREEN/BLUE subsystems:
- prod/ (BLUE harness, configs, scripts, docs)
- nautilus_dolphin/ (GREEN Nautilus-native impl + dvae/ preserved)
- adaptive_exit/ (AEM engine + models/bucket_assignments.pkl)
- Observability/ (EsoF advisor, TUI, dashboards)
- external_factors/ (EsoF producer)
- mc_forewarning_qlabs_fork/ (MC regime/envelope)

Excludes runtime caches, logs, backups, and reproducible artifacts per .gitignore.

nautilus_dolphin/test_catalog_signal.py

@@ -0,0 +1,29 @@
+
+import pandas as pd
+from nautilus_trader.core.nautilus_pyo3 import Signal
+from nautilus_trader.persistence.catalog import ParquetDataCatalog
+from pathlib import Path
+
+def test_write_signal():
+    catalog_path = Path("test_catalog")
+    catalog_path.mkdir(exist_ok=True)
+    catalog = ParquetDataCatalog(str(catalog_path))
+    
+    ts = int(pd.Timestamp("2026-02-18 12:00:00").value)
+    import json
+    sig = Signal(
+        name="test_signal",
+        value=json.dumps({"test": 123}),
+        ts_event=ts,
+        ts_init=ts
+    )
+    
+    print(f"Writing signal: {sig}")
+    try:
+        catalog.write_data([sig])
+        print("Successfully wrote signal to catalog")
+    except Exception as e:
+        print(f"Failed to write signal: {e}")
+
+if __name__ == "__main__":
+    test_write_signal()