`Uint8Array` pubkeys degrade to plain objects after `localStorage` round-trip

When account data is persisted to `localStorage` and restored on page reload, `Uint8Array` pubkeys are silently converted to plain objects (`{0: 2, 1: 176, …}`). This causes signing to fail with "length of pubkey is incorrect" because the signing pipeline expects a real `Uint8Array`.

See: https://github.com/hyperweb-io/interchain-kit/blob/dcdabc86f80ea1be9a25919b755fd8b2b9b931b2/packages/store/src/wallet-manager/chain-wallet-store.ts#L89-L93

**Reproduction**

1. Connect a Cosmos wallet
2. Perform a successful transaction (works – pubkey is a real `Uint8Array`)
3. Reload the page (account is restored from `localStorage`)
4. Attempt to sign another transaction
5. Transaction fails with "length of pubkey is incorrect"