Support pre-launch/maintenance checklists

# Problem Summary
Vehicles generally have a variety of checks that should occur prior to launching, but are often ignored and not always known about.

# Proposed Solution
Discussion raised [here](https://discuss.bluerobotics.com/t/suggestion-valve-reminder-popup-in-qgc/12465). In particular,

> a “minimal” solution would
> - automatically display a pre-launch checklist when a vehicle is connected
> - have an option to “never show again” (for users who don’t want it)
>
> and an “ideal” solution would additionally
> - optionally allow physically checking off each item as it is completed
> - with an option to disallow continuing until all boxes are checked off
> - allow custom additions
> - presumably read in from some kind of file
> - possibly even stored on the autopilot itself
> - automatically perform some extra checks using vision, e.g.
> - tilt the camera and check that the video feed changes/moves
> - turn up the lights and check that the video gets brighter on average soon afterwards
> - allow lower frequency checks (including recommended maintenance scheduling) to be tracked and presented as relevant
> - _may need integration with BlueOS cloud or with the vehicle autopilot_
> - _could be handled separately_

The issue does not identify files, tests, or an entry point. Start by reviewing the existing vehicle-connection and checklist-related UI, then narrow the work to a defined subset of the proposed behavior with a clear completion condition.

Written by the indexing model from the issue text.