fix: Bug - Local files should be remembered by client

toju-app/src/app/domains/attachment/domain/logic/attachment-blob.rules.ts

@@ -1,6 +1,9 @@
 /** Chunk size used when rebuilding attachment blobs from disk without blocking the UI thread. */
 export const ATTACHMENT_BLOB_READ_CHUNK_SIZE_BYTES = 256 * 1024;
 
+/** Number of bytes encoded per chunk to keep base64 encoding off the call stack. */
+const BASE64_ENCODE_CHUNK_SIZE = 0x8000;
+
 /** Decode a base64 payload into bytes for Blob construction. */
 export function decodeBase64ToUint8Array(base64: string): Uint8Array {
   const binary = atob(base64);
@@ -13,6 +16,19 @@ export function decodeBase64ToUint8Array(base64: string): Uint8Array {
   return bytes;
 }
 
+/** Encode bytes into a base64 payload, chunked so large buffers cannot overflow the call stack. */
+export function encodeUint8ArrayToBase64(bytes: Uint8Array): string {
+  let binary = '';
+
+  for (let offset = 0; offset < bytes.length; offset += BASE64_ENCODE_CHUNK_SIZE) {
+    const chunk = bytes.subarray(offset, offset + BASE64_ENCODE_CHUNK_SIZE);
+
+    binary += String.fromCharCode(...chunk);
+  }
+
+  return btoa(binary);
+}
+
 /** Yield control back to the browser so long attachment hydration cannot freeze Electron. */
 export function yieldToAttachmentHydrationLoop(): Promise<void> {
   return new Promise((resolve) => {