Go CLI: embed and rerank (#14735)

### What problem does this PR solve?

```
RAGFlow(user)> embed text 'what is rag' 'who are you' with 'embedding-3@test@zhipu-ai' dimension 16;
+-----------+-------+
| dimension | index |
+-----------+-------+
| 16        | 0     |
| 16        | 1     |
+-----------+-------+

RAGFlow(user)> rerank query 'what is rag' document 'rag is retrieval augment generation' 'rag need llm' 'famous rag project includes ragflow' with 'rerank@test@zhipu-ai' top 2;
+-------+-----------------+
| index | relevance_score |
+-------+-----------------+
| 0     | 1               |
| 2     | 0.99999976      |
+-------+-----------------+
```

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

internal/handler/providers.go

@@ -894,3 +894,156 @@ func (h *ProviderHandler) ChatToModel(c *gin.Context) {
 		"answer":            response.Answer,
 	})
 }
+
+type EmbedTextRequest struct {
+	ProviderName *string  `json:"provider_name"`
+	InstanceName *string  `json:"instance_name"`
+	ModelName    *string  `json:"model_name"`
+	Texts        []string `json:"texts"`
+	Dimension    int      `json:"dimension"`
+}
+
+func (h *ProviderHandler) EmbedText(c *gin.Context) {
+	var req EmbedTextRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		println("JSON bind error: %v (type: %T)", err, err)
+		c.JSON(http.StatusOK, gin.H{
+			"code":    common.CodeBadRequest,
+			"message": err.Error(),
+		})
+		return
+	}
+
+	if req.ProviderName == nil || *req.ProviderName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    400,
+			"message": "Provider name is required",
+		})
+		return
+	}
+
+	if req.InstanceName == nil || *req.InstanceName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    400,
+			"message": "Instance name is required",
+		})
+		return
+	}
+
+	if req.ModelName == nil || *req.ModelName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    400,
+			"message": "Model name is required",
+		})
+		return
+	}
+
+	userID := c.GetString("user_id")
+
+	apiConfig := models.APIConfig{
+		ApiKey: nil,
+		Region: nil,
+	}
+
+	embeddingConfig := models.EmbeddingConfig{
+		Dimension: req.Dimension,
+	}
+
+	// Non-stream response
+	var response *models.EmbeddingResponse
+	var errorCode common.ErrorCode
+	var err error
+
+	response, errorCode, err = h.modelProviderService.EmbedText(*req.ProviderName, *req.InstanceName, *req.ModelName, userID, req.Texts, &apiConfig, &embeddingConfig)
+
+	if err != nil {
+		c.JSON(http.StatusOK, gin.H{
+			"code":    errorCode,
+			"message": err.Error(),
+		})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"code":    0,
+		"data":    response.Data,
+		"message": "success",
+	})
+}
+
+type RerankDocumentRequest struct {
+	ProviderName *string  `json:"provider_name"`
+	InstanceName *string  `json:"instance_name"`
+	ModelName    *string  `json:"model_name"`
+	Query        string   `json:"query"`
+	Documents    []string `json:"documents"`
+	TopN         int      `json:"top_n"`
+}
+
+func (h *ProviderHandler) RerankDocument(c *gin.Context) {
+	var req RerankDocumentRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		println("JSON bind error: %v (type: %T)", err, err)
+		c.JSON(http.StatusOK, gin.H{
+			"code":    common.CodeBadRequest,
+			"message": err.Error(),
+		})
+		return
+	}
+
+	if req.ProviderName == nil || *req.ProviderName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    400,
+			"message": "Provider name is required",
+		})
+		return
+	}
+
+	if req.InstanceName == nil || *req.InstanceName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    400,
+			"message": "Instance name is required",
+		})
+		return
+	}
+
+	if req.ModelName == nil || *req.ModelName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    400,
+			"message": "Model name is required",
+		})
+		return
+	}
+
+	userID := c.GetString("user_id")
+
+	apiConfig := models.APIConfig{
+		ApiKey: nil,
+		Region: nil,
+	}
+
+	rerankConfig := models.RerankConfig{
+		TopN: req.TopN,
+	}
+
+	// Non-stream response
+	var response *models.RerankResponse
+	var errorCode common.ErrorCode
+	var err error
+
+	response, errorCode, err = h.modelProviderService.RerankDocument(*req.ProviderName, *req.InstanceName, *req.ModelName, userID, req.Query, req.Documents, &apiConfig, &rerankConfig)
+
+	if err != nil {
+		c.JSON(http.StatusOK, gin.H{
+			"code":    errorCode,
+			"message": err.Error(),
+		})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"code":    0,
+		"data":    response.Data,
+		"message": "success",
+	})
+}