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.

web/app/dashboard/ai-workflows/_components/variable-selector.tsx

@@ -0,0 +1,35 @@
+"use client"
+
+import { OptionCombobox } from "@/components/option-combobox"
+
+import type { WorkflowVariableRef, WorkflowVariableSelector } from "./workflow-utils"
+
+export function VariableSelector({
+  value,
+  variables,
+  onChange,
+}: {
+  value?: WorkflowVariableSelector
+  variables: WorkflowVariableRef[]
+  onChange: (value: WorkflowVariableSelector) => void
+}) {
+  const options = variables.map((item) => ({
+    value: `${item.nodeId}.${item.field}`,
+    label: `${item.nodeName}.${item.field} · ${item.type}`,
+  }))
+  const selectedValue = value?.nodeId && value.field ? `${value.nodeId}.${value.field}` : ""
+
+  return (
+    <OptionCombobox
+      value={selectedValue}
+      options={options}
+      placeholder="选择变量"
+      searchPlaceholder="搜索变量"
+      emptyText="没有可用上游变量"
+      onChange={(nextValue) => {
+        const [nodeId, ...fieldParts] = nextValue.split(".")
+        onChange({ nodeId, field: fieldParts.join(".") })
+      }}
+    />
+  )
+}