feat(storage): 定义 SessionMeta 和 MessageMeta 数据结构

src/storage/message.rs

@@ -1 +1,15 @@
-// Message CRUD 操作占位符
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct MessageMeta {
+    pub id: String,
+    pub session_id: String,
+    pub seq: i64,
+    pub role: String,
+    pub content: String,
+    pub media_refs: Option<String>,
+    pub tool_call_id: Option<String>,
+    pub tool_name: Option<String>,
+    pub tool_calls: Option<String>,
+    pub created_at: i64,
+}

src/storage/session.rs

@@ -1 +1,15 @@
-// Session CRUD 操作占位符
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SessionMeta {
+    pub id: String,
+    pub channel: String,
+    pub chat_id: String,
+    pub dialog_id: String,
+    pub title: String,
+    pub created_at: i64,
+    pub last_active_at: i64,
+    pub message_count: i64,
+    pub routing_info: Option<String>,
+    pub deleted_at: Option<i64>,
+}