GOCli check provider region (#15474)

## Summary
- add CLI command `CHECK PROVIDER 'provider_name' REGION 'region_name'
KEY 'api_key';`
  - route the command through CLI parser and command dispatcher
- call `GET /api/v1/providers/:provider_name/connection` with `region`
and `api_key`

  ## Testing
  - `go test ./internal/cli/...`
  - manually verified CLI command parsing and request flow

internal/cli/user_command.go

@@ -2551,6 +2551,64 @@ func (c *RAGFlowClient) CheckProviderConnection(cmd *Command) (ResponseIf, error
 	return &result, nil
 }
 
+func (c *RAGFlowClient) CheckProviderWithKey(cmd *Command) (ResponseIf, error) {
+	if c.HTTPClient.APIToken == "" && c.HTTPClient.LoginToken == "" {
+		return nil, fmt.Errorf("API token not set. Please login first")
+	}
+	if c.ServerType != "user" {
+		return nil, fmt.Errorf("this command is only allowed in USER mode")
+	}
+
+	providerName, ok := cmd.Params["provider_name"].(string)
+	if !ok || providerName == "" {
+		return nil, fmt.Errorf("provider name not provided")
+	}
+	region, ok := cmd.Params["region"].(string)
+	if !ok || region == "" {
+		return nil, fmt.Errorf("region not provided")
+	}
+	apiKey, ok := cmd.Params["api_key"].(string)
+	if !ok {
+		return nil, fmt.Errorf("api_key not provided")
+	}
+	baseURL, _ := cmd.Params["base_url"].(string)
+
+	var apiKeyValue interface{}
+	if apiKey != "" {
+		apiKeyValue = apiKey
+	} else {
+		apiKeyValue = nil
+	}
+
+	url := fmt.Sprintf("/providers/%s/connection", providerName)
+
+	payload := map[string]interface{}{
+		"region":  region,
+		"api_key": apiKeyValue,
+	}
+	if baseURL != "" {
+		payload["base_url"] = baseURL
+	}
+
+	resp, err := c.HTTPClient.Request("GET", url, "api", nil, payload)
+	if err != nil {
+		return nil, fmt.Errorf("failed to check provider connection with key: %w", err)
+	}
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("failed to check provider connection: HTTP %d, body: %s", resp.StatusCode, string(resp.Body))
+	}
+
+	var result SimpleResponse
+	if err = json.Unmarshal(resp.Body, &result); err != nil {
+		return nil, fmt.Errorf("check provider connection failed: invalid JSON (%w)", err)
+	}
+	if result.Code != 0 {
+		return nil, fmt.Errorf("%s", result.Message)
+	}
+	result.Duration = resp.Duration
+	return &result, nil
+}
+
 // UseModel sets the current model for chat
 func (c *RAGFlowClient) UseModel(cmd *Command) (ResponseIf, error) {
 	if c.HTTPClient.APIToken == "" && c.HTTPClient.LoginToken == "" {