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_benchmark_candidate_review.py

@@ -0,0 +1,111 @@
+from scripts.review_benchmark_candidates import review
+
+from gewu.domain.validation import assertion_digest
+
+
+def _inputs():
+    extractions = {
+        "extract-1": {
+            "extraction_id": "extract-1",
+            "source_revision_id": "source-1",
+            "blocks": [{"block_id": "block-1", "page": 1, "normalized_text": "The sky is blue."}],
+        }
+    }
+    item = {
+        "source_stage": "review",
+        "storage_state": "evaluated; needs-review",
+        "evaluation": {"status": "needs-review", "eligible_for_auto_accept": False},
+        "proposal": {
+            "proposal_id": "proposal-1",
+            "revision": 1,
+            "operations": [
+                {
+                    "node": {
+                        "claims": [
+                            {
+                                "claim_id": "claim-1",
+                                "text": "The sky is blue.",
+                                "evidence": [
+                                    {
+                                        "source_revision_id": "source-1",
+                                        "extraction_id": "extract-1",
+                                        "assertion_digest": assertion_digest("The sky is blue."),
+                                        "quote": "The sky is blue.",
+                                        "locator": {
+                                            "block_id": "block-1",
+                                            "start": 0,
+                                            "end": 16,
+                                            "page": 1,
+                                        },
+                                    }
+                                ],
+                            }
+                        ]
+                    }
+                }
+            ],
+        },
+    }
+    return [item], extractions
+
+
+def test_valid_evidence_does_not_clear_protected_owner_review():
+    items, extractions = _inputs()
+
+    result = review(items, extractions, input_sha256="b" * 64)
+
+    assert result["summary"]["evidence_bindings_valid"] == 1
+    assert result["items"][0]["recommendation"] == "defer"
+    assert result["summary"]["owner_decisions_written"] == 0
+    assert result["summary"]["canonical_records_written"] == 0
+
+
+def test_invalid_quote_recommends_revision_without_mutating_input():
+    items, extractions = _inputs()
+    items[0]["proposal"]["operations"][0]["node"]["claims"][0]["evidence"][0]["quote"] = (
+        "The sky is green."
+    )
+    original = items[0]["proposal"]["operations"][0]["node"]["claims"][0]["evidence"][0]["quote"]
+
+    result = review(items, extractions, input_sha256="c" * 64)
+
+    assert result["items"][0]["recommendation"] == "revise-candidate"
+    assert "QUOTE_SPAN_MISMATCH" in result["items"][0]["claims"][0]["issues"]
+    assert (
+        items[0]["proposal"]["operations"][0]["node"]["claims"][0]["evidence"][0]["quote"]
+        == original
+    )
+
+
+def test_missing_evidence_is_reported_for_each_claim():
+    items, extractions = _inputs()
+    items[0]["proposal"]["operations"][0]["node"]["claims"][0]["evidence"] = []
+
+    result = review(items, extractions, input_sha256="d" * 64)
+
+    assert result["items"][0]["claims"][0]["issues"] == ["CLAIM_EVIDENCE_REQUIRED"]
+    assert result["items"][0]["recommendation"] == "revise-candidate"
+
+
+def test_assertion_digest_is_bound_to_the_exact_claim_text():
+    items, extractions = _inputs()
+    evidence = items[0]["proposal"]["operations"][0]["node"]["claims"][0]["evidence"][0]
+    evidence["assertion_digest"] = "0" * 64
+
+    result = review(items, extractions, input_sha256="e" * 64)
+
+    assert "ASSERTION_DIGEST_MISMATCH" in result["items"][0]["claims"][0]["issues"]
+
+
+def test_supersession_edges_are_copied_to_advisory_ledger():
+    items, extractions = _inputs()
+    edge = {"relation": "corrects", "source": "old-node", "target": "new-node"}
+    items[0]["source_stage"] = "supersession"
+    items[0]["proposal"]["operations"].append({"edge": edge})
+
+    result = review(items, extractions, input_sha256="e" * 64)
+
+    row = result["items"][0]
+    assert row["recommendation"] == "defer"
+    assert row["supersession_edges"] == [edge]
+    assert row["supersession_edges_preserved"] == 1