Only recover a session lock no other locker may hold (#15020)

Hyprland lets any client take over a held lock, so a second shell started
beside the desktop judged the real shell's live lock stranded, took it, and
then exited, leaving the session behind the failsafe while the real shell
still reported itself secure. Recovery now waits while any other Quickshell
or hyprlock runs, and gives up if one never exits.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

test/shell.d/lock-stranded-recovery-test.sh

@@ -15,8 +15,8 @@ assert(
 )
 
 assert(
-  /id: strandedLockCheckProc[\s\S]*omarchy-hyprland-session-locked/.test(serviceQml),
-  'the startup check goes through the shared session lock helper'
+  /id: strandedLockCheckProc[\s\S]*omarchy-hyprland-session-lock-stranded \\"\$PPID\\"/.test(serviceQml),
+  'the startup check asks whether a lock has no live locker, skipping this shell'
 )
 
 // "No output to read" taken for "unlocked" leaves the failsafe up for good.