- Add single-encrypt IPC/CLI flow for private key field encryption
- Keep filename empty after generation and validate it on save
- Reorder single-address tabs to p2pk, p2pkh, p2sh, p2wpkh, p2tr
- Rename app to 'Wallet Generator' (index.html, window title, sidebar, package.json)
- Add ~/.wallet-generator/wallet/ as save directory for all generated wallets
- Add save-wallet and get-wallet-dir IPC handlers in Electron main process
- Expose saveWallet/getWalletDir via preload contextBridge
- HDWallet: save JSON to disk with optional encryption, show saved path
- SingleAddress: add Save card with editable filename for all address types