hyprland: fix waybar, power menu icons, and tray handle glyph

- Explicitly start hyprland-session.target in our hl.on("hyprland.start")
  handler so waybar (and other session services) launch even if HM's
  dbus-update-activation-environment chain fails silently upstream

- Power menu: replace plain spaces with bash $'\uXXXX' nerd font glyphs
  (fa-lock, fa-sign-out, fa-refresh, fa-power-off)

- Waybar tray-handle: use builtins.fromJSON to embed U+E0B2 powerline
  filled left-arrow as the drawer indicator

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

settings/hyprland.nix

@@ -200,10 +200,10 @@ in
           let
             powerMenu = pkgs.writeShellScript "power-menu" ''
               choice=$(printf '%s\n' \
-                $'   Lock' \
+                $'\uf023  Lock' \
-                $'   Logout' \
+                $'\uf08b  Logout' \
-                $'   Reboot' \
+                $'\uf01e  Reboot' \
-                $'   Shutdown' \
+                $'\uf011  Shutdown' \
                 | ${pkgs.anyrun}/bin/anyrun \
                     --plugins "${pkgs.anyrun}/lib/libstdin.so" \
                     --show-results-immediately true \
@@ -250,6 +250,9 @@ in
 
             -- Startup
             hl.on("hyprland.start", function()
+              -- Ensure hyprland-session.target starts even if HM's
+              -- dbus-update-activation-environment chain fails upstream.
+              hl.exec_cmd("systemctl --user start hyprland-session.target")
               hl.exec_cmd("mako")
               hl.exec_cmd("nm-applet --indicator")
               hl.exec_cmd("wl-paste --type text --watch cliphist store")
@@ -490,7 +493,7 @@ in
           };
 
           "custom/tray-handle" = {
-            format = ""; # Nerd Font arrow
+            format = builtins.fromJSON ''"\ue0b2"''; # U+E0B2 Nerd Font powerline filled left-arrow
             tooltip = false;
           };