feat(channels): add crash recovery and gateway mode support

- Add session persistence to SessionRouter for crash recovery
- Add loadSession method to AcpBridge for restoring sessions
- Add ChannelBaseOptions to support external router injection
- Refactor start.ts to support both standalone and gateway modes
- Extract config utilities into separate module

This enables channels to recover sessions after bridge crashes and
supports running multiple channels under a gateway process.

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

docs/users/features/channels/overview.md

@@ -4,20 +4,20 @@ Channels let you interact with a Qwen Code agent from messaging platforms like T
 
 ## How It Works
 
-When you run `qwen channel start <name>`, Qwen Code:
+When you run `qwen channel start`, Qwen Code:
 
-1. Reads the channel configuration from your `settings.json`
-2. Spawns an agent process using the [Agent Client Protocol (ACP)](../../developers/architecture)
-3. Connects to the messaging platform (e.g., Telegram) and starts listening for messages
-4. Routes incoming messages to the agent and sends responses back to the chat
+1. Reads channel configurations from your `settings.json`
+2. Spawns a single agent process using the [Agent Client Protocol (ACP)](../../developers/architecture)
+3. Connects to each messaging platform and starts listening for messages
+4. Routes incoming messages to the agent and sends responses back to the correct chat
 
-Each channel runs as a long-lived process that bridges a messaging platform to a Qwen Code agent.
+All channels share one agent process with isolated sessions per user. Each channel can have its own working directory, model, and instructions.
 
 ## Quick Start
 
 1. Set up a bot on your messaging platform (see channel-specific guides: [Telegram](./telegram), [WeChat](./weixin))
 2. Add the channel configuration to `~/.qwen/settings.json`
-3. Run `qwen channel start <name>`
+3. Run `qwen channel start` to start all channels, or `qwen channel start <name>` for a single channel
 
 ## Configuration
 
@@ -228,7 +228,26 @@ All other slash commands (e.g., `/compress`, `/summary`) are forwarded to the ag
 ## Running
 
 ```bash
+# Start all configured channels (shared agent process)
+qwen channel start
+
+# Start a single channel
 qwen channel start my-channel
 ```
 
 The bot runs in the foreground. Press `Ctrl+C` to stop.
+
+### Multi-Channel Mode
+
+When you run `qwen channel start` without a name, all channels defined in `settings.json` start together sharing a single agent process. Each channel maintains its own sessions — a Telegram user and a WeChat user get separate conversations, even though they share the same agent.
+
+Each channel uses its own `cwd` from its config, so different channels can work on different projects simultaneously.
+
+### Crash Recovery
+
+If the agent process crashes unexpectedly, the channel service automatically restarts it and attempts to restore all active sessions. Users can continue their conversations without starting over.
+
+- Sessions are persisted to `~/.qwen/channels/sessions.json` while the service is running
+- On crash: the agent restarts within 3 seconds and reloads saved sessions
+- After 3 consecutive crashes, the service exits with an error
+- On clean shutdown (Ctrl+C): session data is cleared — the next start is always fresh

docs/users/features/channels/telegram.md

@@ -57,7 +57,11 @@ Or add it to a `.env` file that gets sourced before running.
 ## Running
 
 ```bash
+# Start only the Telegram channel
 qwen channel start my-telegram
+
+# Or start all configured channels together
+qwen channel start
 ```
 
 Then open your bot in Telegram and send a message. You should see "Working..." appear immediately, followed by the agent's response.

docs/users/features/channels/weixin.md

@@ -44,7 +44,11 @@ Note: WeChat channels do not use a `token` field — credentials come from the Q
 ### 3. Start the channel
 
 ```bash
+# Start only the WeChat channel
 qwen channel start my-weixin
+
+# Or start all configured channels together
+qwen channel start
 ```
 
 Open WeChat and send a message to the bot. You should see a typing indicator ("...") while the agent processes, followed by the response.