chore: 升级 explore 模型至 MiniMax M2.7 并移除 Grok Code Fast 1 定义

oh-my-opencode.jsonc

@@ -5,7 +5,7 @@
     "hephaestus": { "model": "openai/gpt-5.4", "variant": "medium" },
     "oracle": { "model": "openai/gpt-5.4", "variant": "high" },
     "librarian": { "model": "ai-gateway/minimax-m2.7" },
-    "explore": { "model": "ai-gateway/grok-code-fast-1" },
+    "explore": { "model": "ai-gateway/minimax-m2.7" },
     "multimodal-looker": { "model": "openai/gpt-5.4", "variant": "medium" },
     "prometheus": { "model": "anthropic/claude-opus-4-6", "variant": "max" },
     "metis": { "model": "anthropic/claude-opus-4-6", "variant": "max" },

opencode.jsonc

@@ -88,12 +88,6 @@
         "apiKey": "{env:AI_GATEWAY_API_KEY}"
       },
       "models": {
-        "grok-code-fast-1": {
-          "name": "Grok Code Fast 1",
-          "reasoning": true,
-          "modalities": { "input": ["text"], "output": ["text"] },
-          "limit": { "context": 256000, "output": 10000 }
-        },
         "glm-5.1": {
           "name": "GLM-5.1",
           "reasoning": true,