feat: Enhance AI Workflow with Variable Contracts and Input Mapping

- Added ConfigSchema, InputSchema, OutputSchema, and DefaultInputs to AIWorkflowNodeSpecResponse.
- Implemented BuildAIWorkflowNodeSpecs to include variable contracts for start and send_reply nodes.
- Introduced applyAutoInputMappings to automatically map inputs based on node connections.
- Enhanced validation to check for required input mappings in workflows.
- Updated workflow editor to support variable selection for node inputs.
- Translated node names and labels to Chinese for better localization.
- Added tests for variable mapping and validation logic.

internal/services/ai_workflow_service_test.go

@@ -174,7 +174,9 @@ func validAIWorkflowDefinition() dsl.Definition {
 		EntryNodeID:   "start_1",
 		Nodes: []dsl.Node{
 			{ID: "start_1", Type: "start"},
-			{ID: "reply_1", Type: "send_reply", Config: json.RawMessage(`{"text":"hello"}`)},
+			{ID: "reply_1", Type: "send_reply", Config: json.RawMessage(`{"text":"hello"}`), Inputs: map[string]dsl.VariableSelector{
+				"replyText": {NodeID: "start_1", Field: "userMessage"},
+			}},
 			{ID: "end_1", Type: "end"},
 		},
 		Edges: []dsl.Edge{