Add Markitect bridge and activation quality

tests/fixtures/markitect-invalid-graph.json

@@ -0,0 +1,18 @@
+{
+  "schema_version": "markitect.memory.graph.v1",
+  "id": "invalid-graph",
+  "nodes": [
+    {
+      "id": "node.a",
+      "kind": "decision"
+    }
+  ],
+  "edges": [
+    {
+      "id": "edge.bad",
+      "kind": "depends_on",
+      "source": "node.a",
+      "target": "missing"
+    }
+  ]
+}