fix: initial paragraph can not input more than 48 chars (#2258)

web/utils/var.ts

 import { MAX_VAR_KEY_LENGHT, VAR_ITEM_TEMPLATE, getMaxVarNameLength } from '@/config'
 import { CONTEXT_PLACEHOLDER_TEXT, HISTORY_PLACEHOLDER_TEXT, PRE_PROMPT_PLACEHOLDER_TEXT, QUERY_PLACEHOLDER_TEXT } from '@/app/components/base/prompt-editor/constants'
+
 const otherAllowedRegex = /^[a-zA-Z0-9_]+$/
+
 export const getNewVar = (key: string, type: string) => {
+  const { max_length, ...rest } = VAR_ITEM_TEMPLATE
+  if (type !== 'string') {
+    return {
+      ...rest,
+      type: type || 'string',
+      key,
+      name: key.slice(0, getMaxVarNameLength(key)),
+    }
+  }
   return {
     ...VAR_ITEM_TEMPLATE,
     type: type || 'string',