Removed GTK2 compatibility shims from headers (fe-gtk.h, gtkutil.h), leaving direct GTK3-facing declarations/includes only (and platform-specific guards unrelated to GTK2 kept as-is).
Cleaned GTK2-specific comments/wording now that behavior is GTK3-native (menu accelerator note and emoji/userlist comment blocks).
Updated menu_setting_foreach() to safely handle sessions where menu_item[id] is still NULL by storing it in a local pointer and only toggling check state when it exists. This avoids GTK/GLib criticals during layout/menu synchronization paths while preserving normal behavior for initialized menu items.
Fixed the a few dialog box layout so the scrolled keybindings list expands to fill available vertical space in the window. It now packs the scroller into the parent GtkBox with expand/fill enabled (gtk_box_pack_start(..., TRUE, TRUE, 0)) instead of adding it as a generic container child. This allows the window height to be fully utilized.
Updated GTK helper usages to reference the new ICON_* (and label) macros so GTK3 builds no longer pass stock IDs to button/icon helpers or dialogs, including banlist buttons, DCC windows, rawlog actions, notify dialog/buttons, pevent dialog buttons, tray menu items, and join dialog image helper usage.
