refactor: migrate WASignalGroup to TypeScript and remove deprecated files (#1320)

* refactor: migrate WASignalGroup to TypeScript and remove deprecated files

* chore: remove WASignalGroup JavaScript files from package.json

* refactor: update SenderKeyStore and SenderKeyStateStructure interfaces to export and add deserialize method. Fix types

* chore: lint issue

* refactor: improve constructor type checking and getSeed method in SenderChainKey

* refactor: update key handling to use Buffer for improved consistency

* signal: consistent naming and dir structure + add some missing types

* fix: lint issues

---------

Co-authored-by: Rajeh Taher <rajeh@reforward.dev>

src/Signal/Group/sender-chain-key.ts

@@ -0,0 +1,38 @@
+import { calculateMAC } from 'libsignal/src/crypto'
+import { SenderMessageKey } from './sender-message-key'
+
+export class SenderChainKey {
+	private readonly MESSAGE_KEY_SEED: Uint8Array = Buffer.from([0x01])
+	private readonly CHAIN_KEY_SEED: Uint8Array = Buffer.from([0x02])
+	private readonly iteration: number
+	private readonly chainKey: Buffer
+
+	constructor(iteration: number, chainKey: any) {
+		this.iteration = iteration
+		if (chainKey instanceof Buffer) {
+			this.chainKey = chainKey
+		} else {
+			this.chainKey = Buffer.from(chainKey || [])
+		}
+	}
+
+	public getIteration(): number {
+		return this.iteration
+	}
+
+	public getSenderMessageKey(): SenderMessageKey {
+		return new SenderMessageKey(this.iteration, this.getDerivative(this.MESSAGE_KEY_SEED, this.chainKey))
+	}
+
+	public getNext(): SenderChainKey {
+		return new SenderChainKey(this.iteration + 1, this.getDerivative(this.CHAIN_KEY_SEED, this.chainKey))
+	}
+
+	public getSeed(): Uint8Array {
+		return this.chainKey
+	}
+
+	private getDerivative(seed: Uint8Array, key: Buffer): Uint8Array {
+		return calculateMAC(key, seed)
+	}
+}