fix(home): relaunch waybar on monitor hotplug instead of SIGUSR2 reload

A real DP/HDMI unplug makes Hyprland tear down the layer-shell surfaces on
the surviving monitor and not recreate them, so waybar and the wallpaper
vanish there. A SIGUSR2 reload rereads waybar's config but does not
recreate a bar that was already destroyed, so it left the laptop bar gone.
Kill and restart waybar instead — a fresh process enumerates the current
outputs and draws a bar on each — and add a settle delay before re-pushing
the wallpaper so it lands on the settled geometry. Verified against a real
DP-1 unplug: the LVDS-1 bar and wallpaper survive.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

modules/media.nix

@@ -7,7 +7,7 @@
 # awww-daemon and the boot-time restore from that symlink run as Hyprland
 # `exec-once` (see home.nix).
 
-{ pkgs, ... }:
+{ pkgs, config, ... }:
 
 let
   # setbg: persist the choice as an XDG-data symlink, then set it live. Startup
@@ -21,20 +21,30 @@ let
   # awww-daemon paints only the outputs present when `awww img` last ran and does
   # not repaint a monitor hotplugged afterwards — it comes up on the fill color
   # (black), and a transparent foot on it then shows that black, not the
-  # wallpaper. Symmetric problem on unplug: removing an output makes Hyprland
-  # drop and not recreate the layer-shell surfaces on the surviving monitor, so
+  # wallpaper. Symmetric problem on real DP/HDMI unplug: Hyprland drops the
+  # layer-shell surfaces on the surviving monitor and does not recreate them, so
   # its waybar and wallpaper vanish. Watch Hyprland's event socket and, on either
   # add or remove, re-push the wallpaper (setbg with no arg → all current
-  # outputs) and reload waybar (SIGUSR2 rebuilds its per-output bars). Hyprland
-  # emits both `monitoradded` and `monitoraddedv2`; match only the non-v2 forms
-  # so each side fires once. Runs as a Hyprland exec-once (see home.nix).
+  # outputs) and fully relaunch waybar. A SIGUSR2 reload is not enough — it
+  # rereads config but does not recreate a bar Hyprland already tore down — so
+  # kill and restart, which enumerates the current outputs and draws a bar on
+  # each. The event flaps (several add/remove lines per plug); the loop is
+  # sequential so each pass converges to one waybar. Hyprland emits both
+  # `monitoradded` and `monitoraddedv2`; match only the non-v2 forms so each side
+  # fires once. Runs as a Hyprland exec-once (see home.nix).
+  hyprctl = "${config.wayland.windowManager.hyprland.finalPackage}/bin/hyprctl";
   monitorHotplug = pkgs.writeShellScriptBin "monitor-hotplug" ''
     sock="''${XDG_RUNTIME_DIR}/hypr/''${HYPRLAND_INSTANCE_SIGNATURE}/.socket2.sock"
     ${pkgs.socat}/bin/socat -u UNIX-CONNECT:"$sock" - | while IFS= read -r line; do
       case "$line" in
         "monitoradded>>"* | "monitorremoved>>"*)
-          setbg
-          ${pkgs.procps}/bin/pkill -USR2 -x .waybar-wrapped || true
+          sleep 1                                    # let Hyprland settle the new geometry
+          setbg                                      # re-push wallpaper to all current outputs
+          ${pkgs.procps}/bin/pkill -x waybar || true # relaunch waybar fresh (see comment)
+          i=0
+          while [ $i -lt 6 ] && ${pkgs.procps}/bin/pgrep -x waybar >/dev/null; do sleep 0.3; i=$((i+1)); done
+          ${pkgs.procps}/bin/pkill -9 -x waybar || true
+          ${hyprctl} dispatch exec waybar
           ;;
       esac
     done