SOCKS5 proxy options are parsed, persisted, then silently ignored — wallet traffic goes direct despite --proxy

[tvpeter]

Describe the bug

The application accepts SOCKS5 proxy settings for its blockchain backends, saves them to config.toml, reloads them while running but never applies them. A user who sets --proxy 127.0.0.1:9050 expecting wallet sync to go over Tor is connecting directly to the electrum/esplora server, with no warning and no error.

To Reproduce

• Configure a wallet to point at 127.0.0.1:50100 server and a proxy 127.0.0.1:50200

bdk-cli --network testnet wallet --wallet tor config  --ext-descriptor "<desc>" --int-descriptor "<desc>" \
  --client-type electrum --database-type sqlite  --url "tcp://127.0.0.1:50100"  --proxy "127.0.0.1:50200"

it saves in config.toml.

• Run a sync: bdk-cli --network testnet wallet --wallet tor sync and the proxy was not used.

Expected behavior

• With --proxy set, electrum and esplora connection goes through the SOCKS5 proxy, and none is made directly.
• If the proxy is unreachable or does not speak SOCKS5, the sync fails with an error rather than falling back to a direct connection.
• If a backend cannot honour the setting, the app should say so explicitly, either rejecting the option at config time or warning instead of accepting and discarding it.

Build environment

• BDK-CLI tag/commit: v4.0.0 20d69a1 (originally reported against 5b3cb00, v4.0.0)
• OS+version: macOS 26.6.2
• Rust/Cargo version: 1.98.1
• Rust/Cargo target: aarch64-apple-darwin

Additional context