Spawn shell subprocesses with bash -c instead of bash -lc

Each `bash -lc` starts a login shell that re-sources the profile
(mise activation, /etc/profile.d) on every invocation — ~16 forks per
call versus ~2 for `bash -c` — which taxes every menu/panel/launcher
action the shell shells out for. The session already exports PATH and
env to the shell, so omarchy commands resolve fine under `bash -c`.

Switch the internal/omarchy-owned spawns (theme+background switches,
brightness, monitor scaling, DNS, lock/fingerprint, keyboard-layout
probe, voxtype status, and the `:`/printf state-file writes) to
`bash -c`. Leave `bash -lc` on the sites that run user-configurable
commands (custom bar-widget exec, menu provider/guard scripts,
launcher scan commands, configurable idle/screensaver command), where
a user's command may rely on their login environment.

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

shell/plugins/panels/network/Panel.qml

@@ -262,7 +262,7 @@ Panel {
 
   function copyToClipboard(value) {
     if (!value || !root.bar) return
-    Quickshell.execDetached(["bash", "-lc", "printf %s " + Util.shellQuote(value) + " | wl-copy"])
+    Quickshell.execDetached(["bash", "-c", "printf %s " + Util.shellQuote(value) + " | wl-copy"])
   }
 
   readonly property string icon: Model.connectionIcon(kind, signalStrength)
@@ -271,7 +271,7 @@ Panel {
     if (scanWifi === undefined) scanWifi = false
     if (!detailsProc.running) detailsProc.running = true
     if (!dnsProc.running) {
-      dnsProc.command = ["bash", "-lc", root.dnsCommand("")]
+      dnsProc.command = ["bash", "-c", root.dnsCommand("")]
       dnsProc.running = true
     }
     if (wifiDevice) {
@@ -467,7 +467,7 @@ Panel {
     }
 
     root.pendingDnsProvider = provider
-    actionProc.command = ["bash", "-lc", root.dnsCommand(provider)]
+    actionProc.command = ["bash", "-c", root.dnsCommand(provider)]
     actionProc.running = true
     root.close()
   }