feat: add periodic version check with soft reconnection

Implements automatic version updates that are transparent to users:

- Checks for new WhatsApp Web version every 6 hours (configurable)
- When new version detected, saves it for next natural reconnection
- Emits 'version.update' event so users can track updates
- No disconnection required - WhatsApp naturally reconnects every 30min-2h
- Cleans up interval when socket closes

Configuration:
```typescript
const sock = await makeWASocketAutoVersion({
    auth: state,
    versionCheckIntervalMs: 6 * 60 * 60 * 1000 // 6 hours (default)
})

sock.ev.on('version.update', ({ currentVersion, newVersion, isCritical }) => {
    console.log(`New version: ${newVersion.join('.')}`)
})
```

src/Types/Events.ts

@@ -107,6 +107,18 @@ export type BaileysEventMap = {
 
 	/** Settings and actions sync events */
 	'chats.lock': { id: string; locked: boolean }
+	/**
+	 * Emitted when a new WhatsApp Web version is detected.
+	 * The new version will be used on the next reconnection (soft update).
+	 */
+	'version.update': {
+		/** Previous version */
+		currentVersion: [number, number, number]
+		/** New version detected */
+		newVersion: [number, number, number]
+		/** Whether the update is critical (major version change) */
+		isCritical: boolean
+	}
 	'settings.update':
 		| { setting: 'unarchiveChats'; value: boolean }
 		| { setting: 'locale'; value: string }

src/Types/Socket.ts

@@ -56,6 +56,13 @@ export type SocketConfig = {
 	 * @default false
 	 */
 	fetchLatestVersion: boolean
+	/**
+	 * Interval in milliseconds to check for new WhatsApp Web versions.
+	 * When a new version is detected, it will be used on the next reconnection.
+	 * Set to 0 to disable periodic checks.
+	 * @default 21600000 (6 hours)
+	 */
+	versionCheckIntervalMs: number
 	/** override browser config */
 	browser: WABrowserDescription
 	/** agent used for fetch requests -- uploading/downloading media */