新增: 消息级溯源 P0 地基(ChatMessage.id + ai_messages 拆表 + 迁移 + Repo)

依据消息拆分存储设计 + 消息级溯源设计 P0(地基,P1 溯源/P2 切读待后续):
- df-ai-core ChatMessage 加 id 字段(Option<String> serde 向前兼容)+ new_message_id(AtomicU64+ts 并发安全)
- 6 构造器生成 id,老 JSON 无 id → None 兼容
- df-storage V21 一次原子迁移:建 ai_messages 表 + ai_tool_executions.message_id 列 + 全量数据迁移(分批+坏数据容错+COUNT 幂等)
- AiMessageRecord + AiMessageRepo(insert_batch/list_by_conversation/delete_range/update_status/update_content_by_tool_call_id)
- audit message_id 列补建(conversation_repo/settings 白名单)
- src-tauri title.rs/finalize.rs 字面量占位(P1 接真值)

自验: df-storage 45 passed + df-ai-core 28 passed + workspace EXIT 0

crates/df-storage/src/crud/conversation_repo.rs

@@ -93,6 +93,9 @@ fn ai_tool_execution_from_row(row: &Row<'_>) -> std::result::Result<AiToolExecut
     Ok(AiToolExecutionRecord {
         id: row.get("id")?,
         conversation_id: row.get("conversation_id")?,
+        // F-260619-04:message_id 列老库经 v21 迁移补建。unwrap_or(None) 兜底:
+        // 新库空表直接有列;老库行 ALTER 后 NULL;极端情况(迁移未跑/手工删列)防御。
+        message_id: row.get("message_id").unwrap_or(None),
         tool_call_id: row.get("tool_call_id")?,
         tool_name: row.get("tool_name")?,
         arguments: row.get("arguments")?,
@@ -187,10 +190,10 @@ impl_repo!(
     from_row => |row| ai_tool_execution_from_row(row),
     insert  => |conn, rec| {
         conn.execute(
-            "INSERT INTO ai_tool_executions (id, conversation_id, tool_call_id, tool_name, arguments, result, status, risk_level, requested_at, executed_at, decided_by)
-             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11)",
+            "INSERT INTO ai_tool_executions (id, conversation_id, message_id, tool_call_id, tool_name, arguments, result, status, risk_level, requested_at, executed_at, decided_by)
+             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12)",
             params![
-                rec.id, rec.conversation_id, rec.tool_call_id, rec.tool_name,
+                rec.id, rec.conversation_id, rec.message_id, rec.tool_call_id, rec.tool_name,
                 rec.arguments, rec.result, rec.status, rec.risk_level,
                 rec.requested_at, rec.executed_at, rec.decided_by
             ],
@@ -198,9 +201,9 @@ impl_repo!(
     },
     update  => |conn, rec| {
         conn.execute(
-            "UPDATE ai_tool_executions SET conversation_id = ?1, tool_call_id = ?2, tool_name = ?3, arguments = ?4, result = ?5, status = ?6, risk_level = ?7, requested_at = ?8, executed_at = ?9, decided_by = ?10 WHERE id = ?11",
+            "UPDATE ai_tool_executions SET conversation_id = ?1, message_id = ?2, tool_call_id = ?3, tool_name = ?4, arguments = ?5, result = ?6, status = ?7, risk_level = ?8, requested_at = ?9, executed_at = ?10, decided_by = ?11 WHERE id = ?12",
             params![
-                rec.conversation_id, rec.tool_call_id, rec.tool_name,
+                rec.conversation_id, rec.message_id, rec.tool_call_id, rec.tool_name,
                 rec.arguments, rec.result, rec.status, rec.risk_level,
                 rec.requested_at, rec.executed_at, rec.decided_by, rec.id
             ],