Make Connecting Smarter

## Summary
- Auto-connection could by default connect to the last successful connection, instead of starting in search mode by default
- Manual connection could provide better default ports when selecting Ping1D (9090) or Ping360 (9092) device types. Custom/dev IP and port should be available, but shouldn't come before defaults for standard users.

## Additional information
If user changed the IP subnet last time they used Ping Viewer, they quite likely want to keep that subnet next time. (I'm a bit confused here, I thought Ping Viewer searched for devices on the current computer's subnet rather than a hardcoded one, but maybe not - may need confirmation)

Current manual connection default configuration is set to `192.168.2.2:1234`, which is the default Companion IP (reasonable expectation) and the dev port (less desirable). Current implementation uses the same Entry widget, and hence same value regardless of device type, but ideally specifying a different device type would also change the default connection info, since different devices have different default ports.

> [Relevant forum comment](https://discuss.bluerobotics.com/t/ping-1d-can-not-connect/11330/5):
> You could do a dropdown list on the port section: Ping1D (9090), Ping360 (9092), Custom.
I don’t know how many of us change the IP address of the ROV but even if the PingView does not check the local address mask (in my example 192.168.4.x), it would be great if it instead of always starting in search mode, connects to the last successful connection.
> -Grega (@tunadiver)

Start by reviewing Ping Viewer’s current auto-connection and manual connection flow, including how Ping1D and Ping360 device types select connection settings. Confirm whether the search uses the computer’s subnet, then define the expected behavior for reusing the last successful connection, device-specific default ports, and custom IP/port entry. Done means these connection defaults work consistently for standard users.

Written by the indexing model from the issue text.