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.

tests/test_owner_review_packet.py

@@ -0,0 +1,53 @@
+from scripts.build_owner_review_packet import render
+
+
+def test_review_packet_distinguishes_held_drafts_from_corrections() -> None:
+    items = [
+        {
+            "source_stage": "satie",
+            "storage_state": "evaluated; needs-review; not submitted",
+            "proposal": {
+                "proposal_id": "held-one",
+                "revision": 1,
+                "base_commit": "a" * 40,
+                "operations": [
+                    {
+                        "node": {
+                            "node_id": "node-one",
+                            "node_type": "finding",
+                            "title": "Held finding",
+                            "summary": "Summary",
+                            "claims": [],
+                        }
+                    }
+                ],
+            },
+        },
+        {
+            "source_stage": "supersession",
+            "storage_state": "durably staged; needs-review; no owner receipt",
+            "proposal": {
+                "proposal_id": "correction-one",
+                "revision": 1,
+                "base_commit": "b" * 40,
+                "operations": [
+                    {
+                        "node": {
+                            "node_id": "node-two",
+                            "node_type": "finding",
+                            "title": "Correction finding",
+                            "summary": "Corrected summary",
+                            "claims": [],
+                        }
+                    }
+                ],
+            },
+        },
+    ]
+
+    packet = render(items)
+
+    assert "Keep held; do not create an exception" in packet
+    assert "Approve this replacement for the owner workflow" in packet
+    assert "Proposal base commits may be stale" in packet
+    assert "does not alter GEWU state" in packet