Remove wallet ids and use client pubkeys

Also includes moving to `/:pubkey/settings` etc. routes so we don't do stuff like fetching `selectedWalletId` from the store in each screen.

This would also help in eliminating the case where the same connection string is added multiple times and mainly the instances where wallet ids are decremented by 1 on deleting a wallet, which looks very bad.

Start by tracing the app's routes, screens, and the store usage of selectedWalletId. Replace wallet-ID-based navigation with pubkey routes such as /:pubkey/settings, then verify that duplicate connection strings and wallet-ID decrement behavior on deletion are eliminated.

Written by the indexing model from the issue text.