refactor: modularize portal server and harden session recovery

conversation-display.mjs

@@ -8,6 +8,8 @@ import { stripKnownChatSkillPrompt } from './chat-skills.mjs';
 export const TASK_ROUTING_HINT_RE = /^【TKMind 路由提示】[\s\S]*?\n\n/;
 export const MEMIND_TASK_ORCHESTRATION_RE = /^【Memind 任务编排】[\s\S]*?(?:用户任务：|用户任务:)\s*/u;
 export const MINDSPACE_CONTEXT_RE = /^\[MindSpace 上下文\][\s\S]*?\n\n/;
+export const IMAGE_TURN_SCOPE_SUFFIX_RE =
+  /\n*【本轮图片主题（硬性）】[\s\S]*$/u;
 const USER_IDENTITY_BLOCK_RE = /^\[用户身份\][\s\S]*?\n\n/;
 
 export function stripUserIdentityPrefix(text) {
@@ -63,6 +65,7 @@ export function deriveAssistantFacingText(text) {
 /** Strip agent-only prefixes from persisted user message content for UI display. */
 export function deriveUserFacingText(text) {
   let next = String(text ?? '');
+  next = next.replace(IMAGE_TURN_SCOPE_SUFFIX_RE, '');
   next = stripUserIdentityPrefix(next);
   next = stripTaskRoutingHint(next);
   next = stripMemindTaskOrchestrationPrefix(next);