Add per-display DDC volume range

[ohmyangboy]

What & why

Add per-display DDC Value Range for finer volume control. Rebuild panel controls when a reconnect changes the display ID.

How tested

make check and translation checks passed. Verified volume keys and trackpad slider on Dell S2725DSM.

Checklist

• Builds locally
• Updated Localizable.xcstrings for new strings
• Screenshot included

[didriksg]

I don't want a second slider that sets the top of the volume slider, so I'm closing this one. Each display already has one volume slider, and I want to keep it to one.

For finer steps, hold Option+Shift with the volume keys (since 1.7.0). Each press then moves a quarter step, about 1.5 of 100 on the S2725DSM. Does that cover what you needed? If even the lowest steps are too loud, tell me and I'll look at that.

The display ID change (rebuilding the panel when a reconnect gives a display a new ID) looks like a separate fix. If you saw controls stop working after a reconnect, I'd take that as its own PR.

[ohmyangboy]

That's fair, adding another slider isn't very elegant. Thanks for the explanation.

While Option+Shift works, it’s not quite as convenient as setting a custom DDC range—it requires an extra key combo every time (especially on an external keyboard that need fn + f11/f12).

Also, in my setup, I really need to keep the volume consistently within the very lowest range. DDC-Range is the way to fix it for me. Maybe need another solution.