Add manifest.json with file metadata for project assets

graphify-out/cost.json

@@ -0,0 +1,12 @@
+{
+  "runs": [
+    {
+      "date": "2026-07-14T11:40:04.053012+00:00",
+      "input_tokens": 435411,
+      "output_tokens": 0,
+      "files": 70
+    }
+  ],
+  "total_input_tokens": 435411,
+  "total_output_tokens": 0
+}