OAI Compatible Provider for Copilot集成文档应该根据V4 API更新

[原文件](https://github.com/deepseek-ai/awesome-deepseek-integration/blob/main/docs/oai-compatible-copilot/README_cn.md)最后一段现在显示的还是DeepSeek上一版模型的id和上下文长度：
```
"oaicopilot.baseUrl": "https://api.deepseek.com/v1",
"oaicopilot.models": [
{
"id": "deepseek-chat",
"owned_by": "deepseek",
"context_length": 128000,
"max_tokens": 8000
},
{
"id": "deepseek-reasoner",
"owned_by": "deepseek",
"context_length": 128000,
"max_tokens": 16000
}
]
```

建议改为：
```
"oaicopilot.models": [
{
"id": "deepseek-v4-flash",
"owned_by": "deepseek",
"configId": "DS V4 Flash (High)",
"displayName": "DS V4 Flash (High)",
"context_length": 1000000,
"max_tokens": 384000,
"include_reasoning_in_request": true,
"thinking": {
"type": "enabled"
},
"reasoning_effort": "high"
},
{
"id": "deepseek-v4-flash",
"owned_by": "deepseek",
"configId": "DS V4 Flash (Max)",
"displayName": "DS V4 Flash (Max)",
"context_length": 1000000,
"max_tokens": 384000,
"include_reasoning_in_request": true,
"thinking": {
"type": "enabled"
},
"reasoning_effort": "max"
},
{
"id": "deepseek-v4-pro",
"owned_by": "deepseek",
"configId": "DS V4 Pro (High)",
"displayName": "DS V4 Pro (High)",
"context_length": 1000000,
"max_tokens": 384000,
"include_reasoning_in_request": true,
"thinking": {
"type": "enabled"
},
"reasoning_effort": "high"
},
{
"id": "deepseek-v4-pro",
"owned_by": "deepseek",
"configId": "DS V4 Pro (Max)",
"displayName": "DS V4 Pro (Max)",
"context_length": 1000000,
"max_tokens": 384000,
"include_reasoning_in_request": true,
"thinking": {
"type": "enabled"
},
"reasoning_effort": "max"
}
],
```

注意：
1. 在使用此API时需要加上`"include_reasoning_in_request": true`，否则插件不会将上一轮的`reasoning_content`自动拼接到下一轮的请求中，从而导致DeepSeek API报错。
2. 模型中的id必须和DeepSeek官方API中的id相符，否则会提示找不到模型。但为了区分pro / flash模型和思考强度，我自己加入了`configId`, `displayName`, `thinking` & `reasoning_effort`。其余用户可以根据自己的需要修改或删减相关参数。