Ship default config/panels/themes with the app: --init, XDG discovery, build/CI bundling

- tui-wm --init [DIR] writes an embedded default config.toml,
  panels/topbar.toml and themes/{dark,light}.toml (default target
  ~/.config/tui-wm, existing files untouched)
- Config discovery: ./config.toml wins, otherwise ~/.config/tui-wm/
  is used (process switches working dir there so panels/themes/saves/
  hot-reload all resolve consistently); spawned PTYs still start in
  the user's original working directory
- VS Code build tasks copy themes/ into builds/, dist/ sample configs
  refreshed with all new keys and the settings gear
- CI release now also uploads tui-wm-config.tar.gz (config + panels +
  themes) alongside the binaries

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

dist/linux/panels/topbar.toml

@@ -1,21 +1,25 @@
-# Topbar – Linux
+# Standardpanel för TUI-WM (skapad av `tui-wm --init`)
 
 [[item]]
 label = "Terminal"
 action = { type = "spawn_terminal" }
 
+# Inbyggda inställningar (tema/panel/skugga/scrollbar)
+[[item]]
+label = "≡ Inställningar"
+action = { type = "spawn_settings" }
+
 [[item]]
 label = "Exit"
 action = { type = "exit" }
 
-# Klocka – uppdateras varje sekund
+# Status-widgets (körs periodiskt, visas till höger)
 [[status]]
 command = "date '+%H:%M:%S'"
 interval = 1
 width = 10
 align = "right"
 
-# Datum – uppdateras varje minut
 [[status]]
 command = "date '+%Y-%m-%d'"
 interval = 60