fix: use MACOS UserAgent for Android browser to fix pair code registration

The web protocol (WA\x06\x03) requires a web-compatible UserAgent.
Using SMB_ANDROID in the UserAgent caused pair code registration to
fail with "cannot connect device" even though the phone confirmation
appeared. The Android identity is now only set in DeviceProps.platformType
(ANDROID_PHONE) in the registration node, which correctly determines
the display name in "Linked Devices" as "Android (14)".

Changes:
- getUserAgent(): always returns MACOS platform and Desktop device
- getClientPayload(): always includes webInfo (no longer skipped for Android)
- Remove unused isAndroidBrowser import from validate-connection.ts
- Update pair code comments documenting tested platform IDs
- Add structured logging to pair code request

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Socket/socket.ts

@@ -1351,14 +1351,23 @@ export const makeSocket = (config: SocketConfig) => {
 			name: '~'
 		}
 
-		// Pair code with Android browser doesn't work (WA server rejects the
-		// companion registration). When Android is detected, fall back to the
-		// Chrome/macOS platform values that are known to work.
+		// Pair code companion_platform_id must be Chrome (1) when using Android
+		// browser preset. ANDROID_PHONE (16) causes silent timeout (server ignores),
+		// UWP (21) causes "cannot connect device" rejection. Only Chrome (1) works
+		// for pair code via web protocol (WA\x06\x03). The device still appears as
+		// "Android" in linked devices because DeviceProps.platformType=ANDROID_PHONE
+		// is set separately in the registration node.
 		const isAndroid = isAndroidBrowser(browser)
 		const pairPlatformId = isAndroid ? getPlatformId('Chrome') : getPlatformId(browser[1])
 		const pairPlatformDisplay = isAndroid ? 'Chrome (Mac OS)' : `${browser[1]} (${browser[0]})`
 
-		logger.info(`\uD83D\uDD17 Pair code requested | companion: ${pairPlatformDisplay} | ${isAndroid ? 'android override \u2192 Chrome' : 'native platform'}`)
+		logger.info({
+			pairCode: pairingCode,
+			jid: authState.creds.me.id,
+			companionPlatformId: pairPlatformId,
+			companionPlatformDisplay: pairPlatformDisplay,
+			isAndroid,
+		}, `pair code requested | companion: ${pairPlatformDisplay} | ${isAndroid ? 'android override -> Chrome' : 'native platform'}`)
 
 		ev.emit('creds.update', authState.creds)
 		await sendNode({

src/Utils/validate-connection.ts

@@ -9,25 +9,27 @@ import {
 } from '../Defaults'
 import type { AuthenticationCreds, SignalCreds, SocketConfig } from '../Types'
 import { type BinaryNode, getBinaryNodeChild, jidDecode, S_WHATSAPP_NET } from '../WABinary'
-import { isAndroidBrowser } from './browser-utils'
 import { Curve, hmacSign } from './crypto'
 import { encodeBigEndian } from './generics'
 import { createSignalIdentity } from './signal'
 
 const getUserAgent = (config: SocketConfig): proto.ClientPayload.IUserAgent => {
-	const isAndroid = isAndroidBrowser(config.browser)
+	// Always use MACOS/Desktop identity for UserAgent — we connect via web
+	// protocol (WA\x06\x03) so the server expects a web-like UserAgent.
+	// Using SMB_ANDROID here causes pair code registration to fail with
+	// "não é possível conectar" even though the phone shows the confirmation.
+	// Android identity is only set in DeviceProps (registration node) which
+	// determines the display name in "Linked Devices".
 	return {
 		appVersion: {
 			primary: config.version[0],
 			secondary: config.version[1],
 			tertiary: config.version[2]
 		},
-		platform: isAndroid
-			? proto.ClientPayload.UserAgent.Platform.SMB_ANDROID
-			: proto.ClientPayload.UserAgent.Platform.MACOS,
+		platform: proto.ClientPayload.UserAgent.Platform.MACOS,
 		releaseChannel: proto.ClientPayload.UserAgent.ReleaseChannel.RELEASE,
-		osVersion: isAndroid ? config.browser[0] : '0.1',
-		device: isAndroid ? 'Android' : 'Desktop',
+		osVersion: '0.1',
+		device: 'Desktop',
 		osBuildNumber: '0.1',
 		localeLanguageIso6391: 'en',
 		mnc: '000',
@@ -58,11 +60,8 @@ const getClientPayload = (config: SocketConfig) => {
 	const payload: proto.IClientPayload = {
 		connectType: proto.ClientPayload.ConnectType.WIFI_UNKNOWN,
 		connectReason: proto.ClientPayload.ConnectReason.USER_ACTIVATED,
-		userAgent: getUserAgent(config)
-	}
-
-	if (!isAndroidBrowser(config.browser)) {
-		payload.webInfo = getWebInfo(config)
+		userAgent: getUserAgent(config),
+		webInfo: getWebInfo(config)
 	}
 
 	return payload