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/adapters/test_sqlite_node_removals.py

@@ -0,0 +1,48 @@
+from datetime import UTC, datetime, timedelta
+
+import pytest
+
+from gewu.adapters.sqlite_node_removals import RemovalConflict, SQLiteNodeRemovalStore
+
+
+def test_removed_node_is_hidden_until_restored_and_restore_window_is_seven_days(tmp_path) -> None:
+    store = SQLiteNodeRemovalStore(tmp_path / "node-removals.sqlite3")
+    removed = store.request("dome", "node-a", "A node", "editor")
+
+    assert store.is_hidden("dome", "node-a")
+    assert store.list_restorable("dome") == (removed,)
+    restore_window = datetime.fromisoformat(removed.restore_until) - datetime.fromisoformat(
+        removed.requested_at
+    )
+    assert restore_window == timedelta(days=7)
+
+    restored = store.restore("dome", "node-a", "editor")
+    assert restored == removed
+    assert not store.is_hidden("dome", "node-a")
+    assert store.list_restorable("dome") == ()
+
+
+def test_expired_removal_stays_hidden_and_cannot_be_restored(tmp_path) -> None:
+    store = SQLiteNodeRemovalStore(tmp_path / "node-removals.sqlite3")
+    removed = store.request("dome", "node-a", "A node", "editor")
+    with store._connect() as connection:
+        connection.execute(
+            "UPDATE node_removals SET restore_until=? WHERE removal_id=?",
+            ((datetime.now(UTC) - timedelta(seconds=1)).isoformat(), removed.removal_id),
+        )
+
+    assert store.is_hidden("dome", "node-a")
+    assert store.list_restorable("dome") == ()
+    with pytest.raises(RemovalConflict, match="expired"):
+        store.restore("dome", "node-a", "editor")
+
+
+def test_removal_survives_store_reopen_and_duplicate_removal_is_rejected(tmp_path) -> None:
+    path = tmp_path / "node-removals.sqlite3"
+    store = SQLiteNodeRemovalStore(path)
+    store.request("dome", "node-a", "A node", "editor")
+    reopened = SQLiteNodeRemovalStore(path)
+
+    assert reopened.is_hidden("dome", "node-a")
+    with pytest.raises(RemovalConflict):
+        reopened.request("dome", "node-a", "A node", "editor")