feat(server): add recipe-based model management (#2176)

examples/server/recipes/sensenova-u15.json

@@ -0,0 +1,24 @@
+{
+  "schema_version": 1,
+  "id": "sensenova-u15",
+  "name": "SenseNova U1.5",
+  "description": "Bundled MoT checkpoint.",
+  "model_url": "https://huggingface.co/sensenova/SenseNova-U1.5-8B-MoT",
+  "slots": [
+    {
+      "id": "model",
+      "required": true
+    }
+  ],
+  "defaults": {
+    "flow_shift": 3.0,
+    "cfg_scale": 4,
+    "steps": 20,
+    "width": 2048,
+    "height": 2048,
+    "sampling_method": "euler"
+  },
+  "features": [
+    "flow_shift"
+  ]
+}