Closes #88. Refactors vault management:

- Merges `secure` back into `db`.
- Removes "is it encrypted" logic.
- Separates vault loading from the daemon.
- Fixes multi-wallet support[^1].
- Compare vaults only by name (for a given wallet), not path.
- Fixes 1Password integration.
- Changes the `Vault` request parameter from `api.VaultInfo` to just the vault name.
- Removes some cruft.

Changelog: refactor
[^1]: The daemon *thought* it could handle multiple wallet paths but it really couldn't since it only tracked a single index database. Now, the daemon maintains a separate Wallet, with its own index, for each wallet path. Multi-wallet use cases are likely very rare but supporting those scenarios actually makes the code more readable IMO.