feat: add Gemini 3.1 Pro × Gemini Web × Deep Think for mythos-craft (#29)

Co-authored-by: 卢盼 <lupan@lupandeMac-Studio.local>

models/gemini-3-1-pro-gemini-web.json

@@ -0,0 +1,17 @@
+{
+  "label": "Gemini 3.1 Pro",
+  "vendor": "Google",
+  "harness": "Gemini Web",
+  "effort": "Deep Think",
+  "artifactDir": "gemini-3-1-pro/gemini-web-deepthink",
+  "order": 41,
+  "runs": {
+    "mythos-craft": {
+      "note": {
+        "zh": "在 Gemini Web 中以 Gemini 3.1 Pro（Deep Think）一次生成，未修改。",
+        "en": "One-shot by Gemini 3.1 Pro (Deep Think) in Gemini Web, unmodified."
+      },
+      "contributor": "lupan-lu"
+    }
+  }
+}