gui: native libadwaita-free UI backend + dark shell; packaging/iso updates

- gui/ui: native GTK4 widget vocabulary (.tn-*) behind the ui.* seam,
  default backend now native; style_apple.css design language
- shell: sidebar/topbar/content all #0f0f0f in dark (matches eww panels)
- new pages: wine, online_accounts
- packaging: tanin-icons (accent folder theme), tanin-calendar, gtklock,
  taninux-gtk3-theme, flatpak install handler
- iso/distro: profile + manifest tweaks (ISO binary not included)

packaging/gtklock/config.ini

@@ -0,0 +1,13 @@
+# gtklock — TANINUX lockscreen config (Fuji greeter look).
+# glib keyfile format. gtklock is launched as: gtklock -d -c <this file>
+[main]
+# stylesheet + wallpaper-as-css-background live next to this file
+style=/home/karim/.config/gtklock/gtklock.css
+# modules (system .so, suffix optional): user avatar+name, and power buttons
+modules=userinfo;powerbar
+# built-in clock — time over date, like the greeter's centre clock
+time-format=%H:%M
+date-format=%A, %d. %B %Y
+# hide the input when idle so the wallpaper+clock stay clean; reveal on keypress
+idle-hide=true
+idle-timeout=15