[FEATURE] Proxy support for SSH/SFTP connections

[gnilobaiter]

This was originally discussed here:
https://github.com/orgs/VoltiusApp/discussions/343

It would be very useful if Voltius supported proxying SSH/SFTP connections through:

• Windows/System Proxy
• SOCKS5 proxy
• HTTP CONNECT proxy

Suggested behavior

Ideally, proxy configuration could be available globally in the application settings, with an optional per-host override.

For example:

Global proxy settings

• Use system proxy
• SOCKS5
• HTTP CONNECT
• No proxy

Per-host settings

• Use global settings
• Use system proxy
• Custom SOCKS5 / HTTP proxy
• Direct connection

Why this is useful

Some users need SSH connections to follow the same proxy/VPN routing configuration as the rest of the system.

Currently, if SSH traffic needs to go through a proxy, it usually requires external tools, manual tunneling, environment-specific configuration, or routing the entire application/system through a VPN.

Native proxy support would make Voltius much more convenient in restricted networks, corporate environments, or setups where only specific traffic should be proxied.

At minimum, support for the Windows system proxy would already be very useful.

[kipavy]

As said in #371 , will be in next release, Thanks