The main window's NSSplitView panels (channel list, user list, chat,
activity log) were collapsing to zero size because:
1. The scroll views inside the split views were missing
translatesAutoresizingMaskIntoConstraints = false, so Auto Layout
couldn't manage their sizes.
2. The inner split views were also missing it.
3. The voice panel had no height constraint, so it expanded to fill
all available space (539px of the 600px window), starving the
outer split view down to 1px tall.
4. The split views had no initial divider positions, so panels
collapsed to zero even when the split view had space.
Add translatesAutoresizingMaskIntoConstraints = false to all four
scroll views and both inner split views, give the voice panel a
96px height constraint, and set initial divider positions after the
window is on screen. The panels now get reasonable space, are
visible on screen, and are reachable by VoiceOver.
Talon
75c2782860