Add GLM SDK Implementation

- Introduced a new GLM SDK for interacting with the GLM (Zhipu AI) API, designed for chat completions and text generation tasks.
- Implemented core components including Client, Service, and SDK layers following Clean Architecture principles.
- Added configuration management, error handling, and structured logging for improved usability and maintainability.
- Included comprehensive documentation and usage examples to facilitate integration and understanding of the SDK's functionality.
- Enhanced the API with features such as chat completion, streaming responses, and model management, ensuring robust interaction with the GLM service.

pkg/glm/interfaces.go

@@ -0,0 +1,29 @@
+package glm
+
+import (
+	"context"
+)
+
+// GLMService defines the interface for GLM service operations
+type GLMService interface {
+	// ChatCompletion performs a chat completion request
+	ChatCompletion(ctx context.Context, req *ChatCompletionRequest) (*ChatCompletionResponse, error)
+
+	// StreamChatCompletion performs a streaming chat completion request
+	StreamChatCompletion(ctx context.Context, req *ChatCompletionRequest, onChunk func(*StreamChatCompletionResponse) error) error
+
+	// ListModels lists available models
+	ListModels(ctx context.Context) (*ModelsResponse, error)
+
+	// Health checks if the GLM service is available
+	Health(ctx context.Context) error
+}
+
+// HTTPClient defines the interface for HTTP operations
+type HTTPClient interface {
+	// Post performs a POST request
+	Post(ctx context.Context, url string, body interface{}, result interface{}) error
+
+	// Get performs a GET request
+	Get(ctx context.Context, url string, result interface{}) error
+}