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/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 */