Voice sessions set systemPrompt to the voice-mode instruction string,
causing every voice conversation to display '你正在通过语音与用户实时对话。请…'
as its title in the chat history list.
Title derivation priority (highest to lowest):
1. metadata.title — explicit title saved by backend on first task
2. metadata.voiceMode == true → '语音对话 M/D HH:mm'
3. Fallback → '对话 M/D HH:mm' based on session createdAt
Implement DB-based conversation message storage (engine-agnostic) that
works across both Claude API and Agent SDK engines. Add ChatGPT/Claude-style
conversation history drawer in Flutter with date-grouped session list,
session switching, and new chat functionality.
Backend: entity, repository, context service, migration 004, session/message
API endpoints. Flutter: ConversationDrawer, sessionId flow from backend
response via SessionInfoEvent, session list/switch/delete support.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
hailin