[READY FOR MERGE] Implement newsletter (#1532)

* feat: implement basic newsletter functionality with socket integration and event handling

* feat: enhance media handling for newsletters with raw media upload support

* feat: working updatePicture, removePicure, adminCount, mute, Unmute

* fix: fetchMessages

* chore: cleanup

* fix: update newsletter metadata path and query ID for consistency. newsletterMetadata works now

* chore: enhance newsletter metadata parsing and error handling

* fix: correct DELETE QueryId value in Newsletter.ts

* chore: split mex stuffs to own file

* chore: remove as any

src/Socket/mex.ts

@@ -0,0 +1,58 @@
+import { Boom } from '@hapi/boom'
+import { BinaryNode } from '../WABinary'
+import { getBinaryNodeChild, S_WHATSAPP_NET } from '../WABinary'
+
+const wMexQuery = (
+	variables: Record<string, unknown>,
+	queryId: string,
+	query: (node: BinaryNode) => Promise<BinaryNode>,
+	generateMessageTag: () => string
+) => {
+	return query({
+		tag: 'iq',
+		attrs: {
+			id: generateMessageTag(),
+			type: 'get',
+			to: S_WHATSAPP_NET,
+			xmlns: 'w:mex'
+		},
+		content: [
+			{
+				tag: 'query',
+				attrs: { query_id: queryId },
+				content: Buffer.from(JSON.stringify({ variables }), 'utf-8')
+			}
+		]
+	})
+}
+
+export const executeWMexQuery = async <T>(
+	variables: Record<string, unknown>,
+	queryId: string,
+	dataPath: string,
+	query: (node: BinaryNode) => Promise<BinaryNode>,
+	generateMessageTag: () => string
+): Promise<T> => {
+	const result = await wMexQuery(variables, queryId, query, generateMessageTag)
+	const child = getBinaryNodeChild(result, 'result')
+	if (child?.content) {
+		const data = JSON.parse(child.content.toString())
+
+		if (data.errors && data.errors.length > 0) {
+			const errorMessages = data.errors.map((err: Error) => err.message || 'Unknown error').join(', ')
+			const firstError = data.errors[0]
+			const errorCode = firstError.extensions?.error_code || 400
+			throw new Boom(`GraphQL server error: ${errorMessages}`, { statusCode: errorCode, data: firstError })
+		}
+
+		const response = dataPath ? data?.data?.[dataPath] : data?.data
+		if (typeof response !== 'undefined') {
+			return response as T
+		}
+	}
+
+	const action = (dataPath || '').startsWith('xwa2_')
+		? dataPath.substring(5).replace(/_/g, ' ')
+		: dataPath?.replace(/_/g, ' ')
+	throw new Boom(`Failed to ${action}, unexpected response structure.`, { statusCode: 400, data: result })
+}