TS 5.7+ ArrayBuffer drift: cast where ArrayBufferLike leaked

TypeScript 5.7 split ArrayBuffer / SharedArrayBuffer at the type level
(ArrayBuffer now exposes resizable/transfer/detached etc; SharedArrayBuffer
doesn't), and parametrized the typed-array constructors so plain
Uint8Array became Uint8Array<ArrayBufferLike>.

The renderer never uses SharedArrayBuffer, so this is type-level only —
narrowing back to ArrayBuffer at the boundaries:

- BinaryReader.readBytes() / .toArrayBuffer() return the underlying
  DataView buffer; cast to ArrayBuffer.
- BinaryWriter.getBuffer() same shape.
- WsSessionCrypto.randomNonce() now returns Uint8Array<ArrayBuffer>
  (it's always backed by a plain ArrayBuffer); aesGcmEncrypt/Decrypt
  nonce parameter retyped accordingly so SubtleCrypto.encrypt accepts
  it as BufferSource.
- ArrayBufferToBase64 now accepts Uint8Array | ArrayBufferLike directly
  (pako/inflate hands back Uint8Array<ArrayBuffer> which the old
  ArrayBuffer-only signature rejected).

packages/communication/src/crypto/WsSessionCrypto.ts

@@ -38,17 +38,17 @@ export async function deriveAesKey(sharedSecret: ArrayBuffer): Promise<CryptoKey
     );
 }
 
-export async function aesGcmEncrypt(key: CryptoKey, nonce: Uint8Array, plaintext: ArrayBuffer): Promise<ArrayBuffer>
+export async function aesGcmEncrypt(key: CryptoKey, nonce: Uint8Array<ArrayBuffer>, plaintext: ArrayBuffer): Promise<ArrayBuffer>
 {
     return window.crypto.subtle.encrypt({ name: 'AES-GCM', iv: nonce, tagLength: GCM_TAG_LEN * 8 }, key, plaintext);
 }
 
-export async function aesGcmDecrypt(key: CryptoKey, nonce: Uint8Array, ciphertextWithTag: ArrayBuffer): Promise<ArrayBuffer>
+export async function aesGcmDecrypt(key: CryptoKey, nonce: Uint8Array<ArrayBuffer>, ciphertextWithTag: ArrayBuffer): Promise<ArrayBuffer>
 {
     return window.crypto.subtle.decrypt({ name: 'AES-GCM', iv: nonce, tagLength: GCM_TAG_LEN * 8 }, key, ciphertextWithTag);
 }
 
-export function randomNonce(): Uint8Array
+export function randomNonce(): Uint8Array<ArrayBuffer>
 {
     const n = new Uint8Array(NONCE_LEN);
     window.crypto.getRandomValues(n);

packages/utils/src/ArrayBufferToBase64.ts

@@ -1,8 +1,8 @@
-export const ArrayBufferToBase64 = (buffer: ArrayBuffer) =>
+export const ArrayBufferToBase64 = (buffer: ArrayBufferLike | Uint8Array) =>
 {
     let binary = '';
 
-    const bytes = new Uint8Array(buffer);
+    const bytes = buffer instanceof Uint8Array ? buffer : new Uint8Array(buffer);
     const len = bytes.byteLength;
 
     for(let i = 0; i < len; i++) (binary += String.fromCharCode(bytes[i]));

packages/utils/src/BinaryReader.ts

@@ -13,7 +13,7 @@ export class BinaryReader implements IBinaryReader
 
     public readBytes(length: number): IBinaryReader
     {
-        const buffer = new BinaryReader(this._dataView.buffer.slice(this._position, this._position + length));
+        const buffer = new BinaryReader(this._dataView.buffer.slice(this._position, this._position + length) as ArrayBuffer);
 
         this._position += length;
 
@@ -77,6 +77,6 @@ export class BinaryReader implements IBinaryReader
 
     public toArrayBuffer(): ArrayBuffer
     {
-        return this._dataView.buffer;
+        return this._dataView.buffer as ArrayBuffer;
     }
 }

packages/utils/src/BinaryWriter.ts

@@ -89,7 +89,7 @@ export class BinaryWriter implements IBinaryWriter
 
     public getBuffer(): ArrayBuffer
     {
-        return this._buffer.buffer;
+        return this._buffer.buffer as ArrayBuffer;
     }
 
     public get position(): number