Start app with the correct controls layout instead of showing the "hide elapsed time"
transition when started on mobile width. It is annoying.
We cannot detect surface width during app widgets assembly, so update the controls
revealers state on first surface update after window is mapped and only if running
on mobile width. Otherwise do not do anything like before which will result in
showing fully revealed controls (default).
Changing transition in middle or when not fully revealed has dire consequences, seems to be a GTK4 bug. Workaround this bug by switching top revealer transition type only when fully revealed.
Bottom revealer motion controller was causing timeout to be cleared. Prevent that by making it child invisible when windowed, which will remove its allocated height and motion events will not be emitted.
Instead of setting hide controls timeout immediately when starting revealing, make the time controls are revealed constant by setting timeout after animation finishes.
Fullscreen bottom controls panel does not look good when progress bar is too long (especially on "ultrawide" displays), so limit its max width to 1720 application-pixels. This should make it still long enough for convenient chapter seeking.
This avoids D&D controllers clash and allows to freely customize how maximize, minimize and close buttons work (differently for e.g. web application) and where are they placed
The "clapper_src" directory name was unusual. This was done to make it work as a widget for other apps. Now that this functionality got removed it can be named simply "src" as recommended by guidelines.
