feat: compare accountability update deltas

docs/financial-fabric-operator-guide.md

@@ -76,6 +76,14 @@ railiance-fabric review-identity <stable-key> \
   --fabric-id fabric.railiance.primary
 ```
 
+To compare a new run with saved review outputs:
+
+```bash
+railiance-fabric discover-roots --delta \
+  --previous-identity-projection previous-identities.json \
+  --previous-ownership-review previous-ownership.json
+```
+
 The financial export must satisfy these invariants:
 
 - every accepted node has resolvable ownership;