Feat: conversation variable & variable assigner node (#7222)

Signed-off-by: -LAN- <laipz8200@outlook.com>
Co-authored-by: Joel <iamjoel007@gmail.com>
Co-authored-by: -LAN- <laipz8200@outlook.com>

web/types/workflow.ts

@@ -1,6 +1,7 @@
 import type { Viewport } from 'reactflow'
 import type {
   BlockEnum,
+  ConversationVariable,
   Edge,
   EnvironmentVariable,
   Node,
@@ -58,6 +59,7 @@ export type FetchWorkflowDraftResponse = {
   updated_at: number
   tool_published: boolean
   environment_variables?: EnvironmentVariable[]
+  conversation_variables?: ConversationVariable[]
 }
 
 export type NodeTracingListResponse = {
@@ -240,3 +242,11 @@ export type NodesDefaultConfigsResponse = {
   type: string
   config: any
 }[]
+
+export type ConversationVariableResponse = {
+  data: (ConversationVariable & { updated_at: number; created_at: number })[]
+  has_more: boolean
+  limit: number
+  total: number
+  page: number
+}