docs: add GMI Cloud provider entry to providers directory (#32914)

Author: isaachuangGMICLOUD

packages/web/src/content/docs/providers.mdx

@@ -1070,6 +1070,35 @@ subscription](https://github.com/features/copilot/plans) to use.
 
 ---
 
+### GMI Cloud
+
+To use GMI Cloud with OpenCode:
+
+1. Head over to the [GMI Cloud console](https://console.gmicloud.ai/) to create an API key. You can also review the [API reference](https://docs.gmicloud.ai/inference-engine/api-reference/llm-api-reference) for the endpoint details.
+
+2. Run the `/connect` command and search for **GMI Cloud**.
+
+   ```txt
+   /connect
+   ```
+
+3. Enter your GMI Cloud API key.
+
+   ```txt
+   ┌ API key
+   │
+   │
+   └ enter
+   ```
+
+4. Run the `/models` command to select the model you want.
+
+   ```txt
+   /models
+   ```
+
+---
+
 ### Google Vertex AI
 
 To use Google Vertex AI with OpenCode: