refactor: extract dashboard and message-runtime from index.ts

- Extract dashboard code into src/dashboard.ts
- Extract message runtime into src/message-runtime.ts
- Improve group-queue with better concurrency handling
- Update agent-runner with enhanced env/config passing
- Simplify DB operations and cleanup unused code
- Update README for Codex SDK architecture

src/db.ts

@@ -249,20 +249,6 @@ export function storeChatMetadata(
   }
 }
 
-/**
- * Update chat name without changing timestamp for existing chats.
- * New chats get the current time as their initial timestamp.
- * Used during group metadata sync.
- */
-export function updateChatName(chatJid: string, name: string): void {
-  db.prepare(
-    `
-    INSERT INTO chats (jid, name, last_message_time) VALUES (?, ?, ?)
-    ON CONFLICT(jid) DO UPDATE SET name = excluded.name
-  `,
-  ).run(chatJid, name, new Date().toISOString());
-}
-
 export interface ChatInfo {
   jid: string;
   name: string;
@@ -286,27 +272,6 @@ export function getAllChats(): ChatInfo[] {
     .all() as ChatInfo[];
 }
 
-/**
- * Get timestamp of last group metadata sync.
- */
-export function getLastGroupSync(): string | null {
-  // Store sync time in a special chat entry
-  const row = db
-    .prepare(`SELECT last_message_time FROM chats WHERE jid = '__group_sync__'`)
-    .get() as { last_message_time: string } | undefined;
-  return row?.last_message_time || null;
-}
-
-/**
- * Record that group metadata was synced.
- */
-export function setLastGroupSync(): void {
-  const now = new Date().toISOString();
-  db.prepare(
-    `INSERT OR REPLACE INTO chats (jid, name, last_message_time) VALUES ('__group_sync__', '__group_sync__', ?)`,
-  ).run(now);
-}
-
 /**
  * Store a message with full content.
  * Only call this for registered groups where message history is needed.
@@ -326,33 +291,6 @@ export function storeMessage(msg: NewMessage): void {
   );
 }
 
-/**
- * Store a message directly.
- */
-export function storeMessageDirect(msg: {
-  id: string;
-  chat_jid: string;
-  sender: string;
-  sender_name: string;
-  content: string;
-  timestamp: string;
-  is_from_me: boolean;
-  is_bot_message?: boolean;
-}): void {
-  db.prepare(
-    `INSERT OR REPLACE INTO messages (id, chat_jid, sender, sender_name, content, timestamp, is_from_me, is_bot_message) VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
-  ).run(
-    msg.id,
-    msg.chat_jid,
-    msg.sender,
-    msg.sender_name,
-    msg.content,
-    msg.timestamp,
-    msg.is_from_me ? 1 : 0,
-    msg.is_bot_message ? 1 : 0,
-  );
-}
-
 export function getNewMessages(
   jids: string[],
   lastTimestamp: string,
@@ -606,6 +544,12 @@ export function setSession(groupFolder: string, sessionId: string): void {
   ).run(groupFolder, SERVICE_AGENT_TYPE, sessionId);
 }
 
+export function deleteSession(groupFolder: string): void {
+  db.prepare(
+    'DELETE FROM sessions WHERE group_folder = ? AND agent_type = ?',
+  ).run(groupFolder, SERVICE_AGENT_TYPE);
+}
+
 export function getAllSessions(): Record<string, string> {
   const rows = db
     .prepare(