Nomad changes

fixtures/contract/config_embedding_plugin.json

@@ -0,0 +1,32 @@
+{
+  "id": "config_embedding_plugin",
+  "description": "Tests EmbeddingModelType::Plugin variant deserialization in ChunkingConfig — config accepts the plugin variant shape; actual dispatch requires a host-language backend registered via register_embedding_backend at runtime",
+  "tags": ["contract", "config", "embeddings", "plugin"],
+  "call": "extract_file_sync",
+  "input": {
+    "path": "pdf/fake_memo.pdf",
+    "config": {
+      "chunking": {
+        "max_chars": 500,
+        "max_overlap": 50,
+        "embedding": {
+          "model": {
+            "type": "plugin",
+            "name": "test-plugin-backend"
+          },
+          "normalize": true,
+          "max_embed_duration_secs": 30
+        }
+      }
+    }
+  },
+  "assertions": [
+    {
+      "type": "not_error"
+    }
+  ],
+  "skip": {
+    "languages": ["python", "rust", "node", "go", "ruby", "elixir", "wasm", "java", "csharp", "php", "r", "dart", "kotlin_android", "swift", "zig"],
+    "reason": "EmbeddingModelType::Plugin requires a host-language backend registered via register_embedding_backend before dispatch; the e2e harness cannot register one. This fixture validates config round-trip (the {\"type\":\"plugin\",\"name\":...} shape is accepted by every binding's EmbeddingConfig)."
+  }
+}