Run notification click actions as safe argv (backport of #7926)

Backport of the notification click-command hardening (PR #7926, merged to
quattro as 43bfe9b9) onto the v4-0-1 release branch. Click actions are argv
vectors run without a shell, omarchy-notification-send calls the Notify D-Bus
method directly via busctl instead of notify-send, and --exec takes the command
as rest-of-line words. Excludes docs/notifications.md, which does not exist on
v4-0-1.

install/user/first-run/install-voxtype.hook

@@ -5,5 +5,5 @@ set -e
 if omarchy-done ensure voxtype-install-invitation; then
   omarchy-notification-send -u critical -g  "Install Dictation with Voxtype" \
     "Click to install voice dictation for Omarchy." \
-    --exec "omarchy-launch-floating-terminal-with-presentation omarchy-voxtype-install"
+    --exec omarchy-launch-floating-terminal-with-presentation omarchy-voxtype-install
 fi

install/user/first-run/setup-agent.hook

@@ -7,5 +7,5 @@ set -e
 if [[ -z $(omarchy-default-agent) ]] && omarchy-done ensure agent-setup-invitation; then
   omarchy-notification-send -u critical -g 󰚩 "Set your default agent" \
     "Let your favorite agent help with Omarchy." \
-    --exec "omarchy menu summon setup.default.agent"
+    --exec omarchy menu summon setup.default.agent
 fi

install/user/first-run/setup-fingerprint.hook

@@ -8,5 +8,5 @@ if omarchy-hw-fingerprint && [[ ! -f /etc/pam.d/omarchy-lock-fingerprint ]] &&
   omarchy-done ensure fingerprint-setup-invitation; then
   omarchy-notification-send -u critical -g 󰈷 "Setup Fingerprint Reader" \
     "Enable sudo and unlocking with your fingerprint." \
-    --exec "omarchy-launch-floating-terminal-with-presentation omarchy-setup-security-fingerprint"
+    --exec omarchy-launch-floating-terminal-with-presentation omarchy-setup-security-fingerprint
 fi

install/user/first-run/wifi.sh

@@ -1,11 +1,11 @@
 notify_update() {
   omarchy-notification-send -u critical -g  "Update System" "Click to update the system." \
-    --exec "omarchy-launch-floating-terminal-with-presentation omarchy-update"
+    --exec omarchy-launch-floating-terminal-with-presentation omarchy-update
 }
 
 notify_wifi() {
   omarchy-notification-send -u critical -g 󰖩 "Setup Wi-Fi" "Click to configure the wireless network." \
-    --exec "omarchy-shell shell toggle omarchy.network"
+    --exec omarchy-shell shell toggle omarchy.network
 }
 
 announce_network() {