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/pages/client/ClientRoot.tsx

@@ -223,7 +223,8 @@ export function ClientRoot({ children }: ClientRootProps) {
                   {startState.status === AsyncStatus.Error && (
                     <Text>{`Failed to start. ${startState.error.message}`}</Text>
                   )}
-                  {loadState.error?.message !== IDB_VERSION_CONFLICT && (
+                  {('error' in loadState ? (loadState as any).error?.message : undefined) !==
+                    IDB_VERSION_CONFLICT && (
                     <Button variant="Critical" onClick={mx ? () => startMatrix(mx) : loadMatrix}>
                       <Text as="span" size="B400">
                         Retry