Exporting key lists does not work

[151henry151]

When trying to export key lists for a bridge/LMDB wallet, I hit several problems in sequence:

1. Backup — Clicking Backup did not open the backup dialog.
2. Other options — After fixing that, clicking Other options did nothing.
3. Export key lists — After fixing that, clicking Export key lists did not open the key list dialog.
4. Private keys in the dialog — After fixing that, the key list dialog opened but private keys (PrivBase58 / PrivHexBE) did not appear for bridge wallet addresses. In some cases the dialog crashed with NameErrors (e.g. PRIVKEYBYTE or computeChecksum undefined in AddressUtils).

So exporting key lists does not work for bridge/LMDB wallets without additional fixes.

Environment: Debian Linux (kernel 6.1.0-41-amd64), built from source following the project’s Linux build instructions (build_instructions/linux/linux.md) with system deps (capnproto, lmdb) and built deps (libbtc, libwebsockets).