修复版本1.0.7的若干问题 (#11)

* fix/ 0:00 audio ui

* fix/ persist memoir image state and collapse voice history

Keep generated chapter images from staying in processing after successful uploads, and restore segmented voice recordings as a single audio message when reopening conversations.

Made-with: Cursor

* fix/ persist local conversation state and stabilize voice UI

Keep CreateMemory conversations driven by Room so recent text and audio survive page exits, and prevent stale 0:00 voice bubbles while list ordering follows the latest local message time.

Made-with: Cursor

* fix/ server-side root cause for conversation list time and message timestamps

- Add Conversation.last_message_at column with migration and index
- Update last_message_at on text message, audio segment, and AI response
- Sort conversation list by COALESCE(last_message_at, started_at) DESC
- Return real per-message timestamps from Redis history instead of now()
- Pass user_message_timestamp through agent pipeline to avoid LLM delay skew
- Remove all debug logging from server, client, and CI workflow
- Restore import json in conversation_agent (was broken by debug removal)
- Client: remove DebugRuntimeLogger, stop sending transcript as text message

Made-with: Cursor

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Co-authored-by: Kevin <kevin@brighteng.org>

api/database/models.py

@@ -51,6 +51,7 @@ class Conversation(Base):
     id = Column(String, primary_key=True)
     user_id = Column(String, ForeignKey("users.id"), nullable=False)
     started_at = Column(DateTime(timezone=True), default=utc_now)
+    last_message_at = Column(DateTime(timezone=True), nullable=True)
     ended_at = Column(DateTime(timezone=True), nullable=True)
     duration_seconds = Column(Integer, default=0)
     summary = Column(Text, nullable=True)