Wallet loading into core fails

Specter Desktop is not showing transactions. In the log I can see a potential problem:

```
2022-06-19T18:21:30.858Z [info] : stderr-SPECTERD: INFO in wallet_manager: Loading test to Bitcoin Core

2022-06-19T18:21:30.898Z [info] : stderr-SPECTERD: WARNING in wallet_manager: Couldn't load wallet test into core. Silently ignored! RPC error: Request error: Wallet file verification failed. Failed to load database path '/mnt/remote/bitcoind/specterc4032b6b796f6588\test'. Path does not exist.
```
Using Specter v1.10.2. Specter server runs locally on a Windows machine. Bitcoind v22 (latest) is on remote Linux server.

`ls` in `./bitcoin` shows:

```
drwx------ 2 btc2 btc2 4096 Jun 19 15:27 'specterc4032b6b796f6588\test'
-rw------- 1 btc2 btc2 16384 Jun 19 13:48 wallet.dat
```
The path looks suspicious (mix of linux and windows paths?).

The log points to wallet_manager while loading a wallet into Bitcoin Core; start by tracing that loading path and reproducing the setup with Specter on Windows and bitcoind on remote Linux. Check how the wallet path is formed across platforms. Done means the wallet loads without the RPC verification error and its transactions appear in Specter.

Written by the indexing model from the issue text.