feat(provider): add support for Grok provider in AI proxy (#2713)

Co-authored-by: 韩贤涛 <601803023@qq.com>

plugins/wasm-go/extensions/ai-proxy/README.md

@@ -158,6 +158,10 @@ DeepSeek 所对应的 `type` 为 `deepseek`。它并无特有的配置字段。
 
 Groq 所对应的 `type` 为 `groq`。它并无特有的配置字段。
 
+#### Grok
+
+Grok 所对应的 `type` 为 `grok`。它并无特有的配置字段。
+
 #### 文心一言（Baidu）
 
 文心一言所对应的 `type` 为 `baidu`。它并无特有的配置字段。
@@ -863,6 +867,76 @@ provider:
 }
 ```
 
+### 使用 OpenAI 协议代理 Grok 服务
+
+**配置信息**
+
+```yaml
+provider:
+  type: grok
+  apiTokens:
+    - 'YOUR_GROK_API_TOKEN'
+```
+
+**请求示例**
+
+```json
+{
+  "messages": [
+    {
+      "role": "system",
+      "content": "You are a helpful assistant that can answer questions and help with tasks."
+    },
+    {
+      "role": "user",
+      "content": "What is 101*3?"
+    }
+  ],
+  "model": "grok-4"
+}
+```
+
+**响应示例**
+
+```json
+{
+  "id": "a3d1008e-4544-40d4-d075-11527e794e4a",
+  "object": "chat.completion",
+  "created": 1752854522,
+  "model": "grok-4",
+  "choices": [
+    {
+      "index": 0,
+      "message": {
+        "role": "assistant",
+        "content": "101 multiplied by 3 is 303.",
+        "refusal": null
+      },
+      "finish_reason": "stop"
+    }
+  ],
+  "usage": {
+    "prompt_tokens": 32,
+    "completion_tokens": 9,
+    "total_tokens": 135,
+    "prompt_tokens_details": {
+      "text_tokens": 32,
+      "audio_tokens": 0,
+      "image_tokens": 0,
+      "cached_tokens": 6
+    },
+    "completion_tokens_details": {
+      "reasoning_tokens": 94,
+      "audio_tokens": 0,
+      "accepted_prediction_tokens": 0,
+      "rejected_prediction_tokens": 0
+    },
+    "num_sources_used": 0
+  },
+  "system_fingerprint": "fp_3a7881249c"
+}
+```
+
 ### 使用 OpenAI 协议代理 Claude 服务
 
 **配置信息**