Refocus lock screen when session secures

[mlmrx]

Summary

• refocus the password field when WlSessionLock.secure becomes true and keyboard input reaches the lock surface
• retain the existing early focus request while closing the secure-state race
• add focused regression coverage for the lock service's secure handler

Fixes #9418

Testing

• bash test/shell.d/lock-focus-test.sh
• bash test/shell.d/lock-blank-fingerprint-test.sh
• bash test/shell.d/lock-stranded-recovery-test.sh
• bash test/shell.d/monitor-recovery-test.sh
• git diff --cached --check