Update the tagline to Beautiful, Fun & Agentic (#144)

Matches omarchy.org and the omarchy repo. The centring math keys off the string length, so the shorter line stays centred.

configs/airootfs/root/configurator

@@ -122,7 +122,7 @@ greeter() {
   printf '\033[%d;1H' "$logo_row"
   gum style --foreground 2 --padding "0 0 0 $PADDING_LEFT" "$(<"$LOGO_PATH")"
 
-  tagline="Beautiful, Fun & Opinionated Linux by DHH"
+  tagline="Beautiful, Fun & Agentic Linux by DHH"
   tpad=$(((cols - ${#tagline}) / 2)); (( tpad < 0 )) && tpad=0
   printf '\033[%d;%dH%s' "$tagline_row" "$((tpad + 1))" "$tagline"