Ensure overrides are visible when predictions are disabled

[bjorkert]

Closes #435

This PR resolves an issue where setting the prediction time to 0 would cause overrides to be calculated with an end date equal to the current time. This made them look like they are ended on the graph and impossible to cancel with a remote command, as they didn't appear to be active.

The fix introduces a minimum display duration for overrides. The code now calculates the maxEndDate by using the greater of the user's predictionToLoad setting or a new minimumFutureDisplayHours constant (defaulting to 1 hour).

This ensures that a long override is always rendered for at least one hour into the future, making it visible and actionable even when prediction lines are turned off.

[marionbarker]

Summary

I reviewed and tested. I will approve as is, but think using 0.25 as minimumFutureDisplayHours is preferred.

Code Review

code review looks good, but I think 0.25 hour would be a better minimum to match the settings allowed for Hours of Prediction.

Test

With dev version, set displayed predictions for 0 hours, set an override and notice the override does appear in the Information Table but I can't see it in the Remote Control options (so can't cancel it).

Build this version and now the override appears on the remote control screen and I can cancel it.

[marionbarker]

Test again. This is definitely better. Graphic below shows minimumFutureDisplayHours at 1 hour on the left and 0.25 hour on the right. In both cases, the Hours of Prediction is set to 0.25 hours.