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_pack_installer.py

@@ -16,7 +16,24 @@ SPEC.loader.exec_module(installer)
 def make_pack(tmp_path: Path) -> Path:
     pack = tmp_path / "pack"
     (pack / "scripts").mkdir(parents=True)
-    (pack / "manifest.json").write_text('{"pack":"fixture"}\n', encoding="utf-8")
+    (pack / "manifest.json").write_text(
+        json.dumps(
+            {
+                "pack_id": "fixture",
+                "pack_version": "1.0.0",
+                "snapshot": {"digest": "a" * 64},
+                "modules": [
+                    {
+                        "module_id": "profile",
+                        "implementation_version": "1.0.0",
+                        "sha256": installer.digest(b"fixture profile\n"),
+                    }
+                ],
+            }
+        )
+        + "\n",
+        encoding="utf-8",
+    )
     (pack / "AGENTS.md").write_text("fixture profile\n", encoding="utf-8")
     return pack