feat: add offerCall and terminateCall for call signaling

Add outgoing call support with offerCall() and terminateCall() functions.
Stanza structures verified via Frida captures on WhatsApp Android v2.26,
matching real voice and video call flows.

- offerCall(jid, isVideo?) sends call offer with correct child nodes
  (privacy, audio×2, video if applicable, net, capability, enc, encopt)
- terminateCall(callId, callTo, ...) sends call termination with optional
  reason and duration attributes
- Both functions exported from the socket chain

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

src/Socket/messages-recv.ts

@@ -536,6 +536,119 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 		await query(stanza)
 	}
 
+	/**
+	 * Offer (initiate) a call to a JID.
+	 * Structure verified via Frida capture on WhatsApp Android v2.26.
+	 *
+	 * @param jid - destination JID (e.g. "5511999999999@s.whatsapp.net" or LID)
+	 * @param isVideo - true for video call, false/undefined for voice
+	 * @returns callId (hex) and stanzaId used in the offer
+	 */
+	const offerCall = async (jid: string, isVideo?: boolean) => {
+		const meId = authState.creds.me?.id
+		if (!meId) throw new Boom('Not authenticated', { statusCode: 401 })
+
+		const callId = randomBytes(16).toString('hex').toUpperCase()
+		const stanzaId = randomBytes(16).toString('hex').toUpperCase()
+
+		const offerContent: BinaryNode[] = [
+			{ tag: 'privacy', attrs: {}, content: undefined },
+			{ tag: 'audio', attrs: { rate: '8000', enc: 'opus' }, content: undefined },
+			{ tag: 'audio', attrs: { rate: '16000', enc: 'opus' }, content: undefined },
+		]
+
+		if (isVideo) {
+			offerContent.push({
+				tag: 'video',
+				attrs: {
+					screen_width: '1080',
+					screen_height: '2400',
+					dec: 'H264,H265,AV1',
+					device_orientation: '0',
+					enc: 'h.264'
+				},
+				content: undefined
+			})
+		}
+
+		offerContent.push(
+			{ tag: 'net', attrs: { medium: '3' }, content: undefined },
+			{ tag: 'capability', attrs: { ver: '1' }, content: undefined },
+			{ tag: 'enc', attrs: { v: '2', type: isVideo ? 'msg' : 'pkmsg' }, content: undefined },
+			{ tag: 'encopt', attrs: { keygen: '2' }, content: undefined },
+		)
+
+		const stanza: BinaryNode = {
+			tag: 'call',
+			attrs: {
+				to: jid,
+				id: stanzaId,
+			},
+			content: [{
+				tag: 'offer',
+				attrs: {
+					'call-creator': meId,
+					'call-id': callId,
+					'device_class': '2013',
+				},
+				content: offerContent
+			}]
+		}
+
+		await query(stanza)
+		return { callId, stanzaId }
+	}
+
+	/**
+	 * Terminate (hang up) an active or ringing call.
+	 * Structure verified via Frida capture on WhatsApp Android v2.26.
+	 *
+	 * @param callId - the call-id from the offer
+	 * @param callTo - JID of the other party
+	 * @param callCreator - JID of who created the call (usually meId for outgoing)
+	 * @param reason - terminate reason (omit for normal hangup, or 'timeout', 'busy', etc.)
+	 * @param duration - call duration in ms (included when call was connected)
+	 */
+	const terminateCall = async (
+		callId: string,
+		callTo: string,
+		callCreator?: string,
+		reason?: string,
+		duration?: number
+	) => {
+		const meId = authState.creds.me?.id
+		if (!meId) throw new Boom('Not authenticated', { statusCode: 401 })
+
+		const terminateAttrs: Record<string, string> = {
+			'call-id': callId,
+			'call-creator': callCreator || meId,
+		}
+
+		if (reason) {
+			terminateAttrs.reason = reason
+		}
+
+		if (typeof duration === 'number') {
+			terminateAttrs.duration = String(duration)
+			terminateAttrs.audio_duration = String(duration)
+		}
+
+		const stanza: BinaryNode = {
+			tag: 'call',
+			attrs: {
+				to: callTo,
+				id: randomBytes(16).toString('hex').toUpperCase(),
+			},
+			content: [{
+				tag: 'terminate',
+				attrs: terminateAttrs,
+				content: undefined
+			}]
+		}
+
+		await query(stanza)
+	}
+
 	const sendRetryRequest = async (node: BinaryNode, forceIncludeKeys = false) => {
 		const { fullMessage } = decodeMessageNode(node, authState.creds.me!.id, authState.creds.me!.lid || '')
 		const { key: msgKey } = fullMessage
@@ -2161,6 +2274,8 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 		sendMessageAck,
 		sendRetryRequest,
 		rejectCall,
+		offerCall,
+		terminateCall,
 		fetchMessageHistory,
 		requestPlaceholderResend,
 		messageRetryManager