feat: replace regime monitor with v2 methodology

app/models/regime_snapshot.py

@@ -8,12 +8,12 @@ from app.database import Base
 
 
 class RegimeSnapshot(Base):
-    """Daily snapshot of the AI/Tech regime-change index.
+    """Daily point-in-time snapshot of the AI/Tech Regime Monitor.
 
     One row per calendar date (unique). ``breakdown_json`` holds the full
-    per-signal breakdown plus the raw inputs, so reads need no recomputation and
-    the 7/30-day trend is just a query over ``total_score``. Decoupled from the
-    rest of the platform: nothing reads this to gate or score trades.
+    ``breakdown_json`` is authoritative for v2 State, Warning, source dates,
+    coverage, and fixed-basket metadata. ``total_score``/``band`` retain the v2
+    State reading for schema compatibility. Nothing reads this to gate trades.
     """
 
     __tablename__ = "regime_snapshots"