chore: upgrade TypeScript 4.9 to 5.9, ESLint 8.29 to 8.57, @typescript-eslint 5 to 7

Resolves all TS2345/TS2347/TS7006 type errors introduced by stricter TypeScript 5.x.
Fix Icons.Settings to Icons.Setting, cast account data returns, fix implicit any.

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

src/app/utils/matrix.ts

@@ -113,7 +113,7 @@ export const encryptFile = async (
 }> => {
   const dataBuffer = await file.arrayBuffer();
   const encryptedAttachment = await encryptAttachment(dataBuffer);
-  const encFile = new File([encryptedAttachment.data], file.name, {
+  const encFile = new File([encryptedAttachment.data], (file as File).name, {
     type: file.type,
   });
   return {