Updated the GTK3 import callback in setup.c to:
open a file chooser titled Import GTK3 Theme ZIP,
enforce a ZIP-focused chooser filter (*.zip, *.ZIP),
call the new backend function,
show success/failure dialogs through setup_theme_show_message,
refresh the GTK3 theme list immediately after successful import.
Updated the GTK3 section button label to Import GTK3 Theme ZIP and added/used new translatable strings for the new button text and import messages.
Simplified away_check by removing comment clutter and keeping only the logic flow, including the WHO batching behavior.
Removed unneeded commentary around lag-check helpers and timer reinitialization to keep the core timer code cleaner and easier to scan.
Updated the Win32 WM_COPYDATA handler to recognize that toggle command and perform minimize/restore behavior:
visible window → iconify
hidden window → show/present
while preserving existing behavior for normal remote commands.
Integrated STS capability handling and connection lifecycle hooks (ignore CAP DEL, trigger upgrades, reschedule on disconnect, new server fields).
Initialized and cleaned up STS state during startup/shutdown to persist policies across sessions.
