feat: online verification, node removals, and knowledge browser

Adds claim-bound online evidence records and citation verification scripts,
node removal transport/adapter, retrieval benchmark and owner-review tooling,
GraphCanvas/SourceDetail knowledge browser UI, and the ingest handoff helper.
Bumps the agents/gewu pack to the online-verification branch.

scripts/export_schemas.py

@@ -26,6 +26,7 @@ from gewu.domain.contracts import (
     ServiceDiagnostics,
     SourceRevisionRecord,
     TypedEdge,
+    OnlineEvidence,
 )
 
 ROOT = Path(__file__).resolve().parents[1]
@@ -53,6 +54,7 @@ MODELS = (
     Scope,
     SourceRevisionRecord,
     TypedEdge,
+    OnlineEvidence,
 )