Add ability to rename hostname manually

Currently, there's no way to edit them

Would be really helpful, especially when builtin hostname detection fails after taking too long (as reported in #5 )

Start by tracing the built-in hostname detection behavior described here and in issue #5, then identify where discovered hostnames are represented and displayed. Add a manual rename path and verify that a user can edit a hostname when detection is slow or incorrect, with the renamed value shown afterward.

Written by the indexing model from the issue text.