fix(lock): lock screen swallowed every keystroke; add Ctrl+L to lock

The renderer-side guard added in v1.0.17 called preventDefault on every
keydown while locked. A keydown's default action IS inserting the
character into the focused field, so the lock screen's password box
received nothing and a locked app could never be unlocked. Menu
accelerators are already stopped in main (before-input-event); the
renderer guard now just skips its own logic.

Also: Ctrl+L locks the screen from anywhere in the app, terminals
included. The chord is only taken when a lock actually engages, so an
unconfigured app keeps Ctrl+L for the shell's clear-screen.

src/shared/i18n/dicts/en/settings.ts

@@ -134,7 +134,7 @@ const settings: Record<string, string> = {
   'settings.lock.lockAtStartup': 'Lock at startup',
   'settings.lock.lockAtStartupDesc': 'Ask for the password right after every launch',
   'settings.lock.lockNow': 'Lock now',
-  'settings.lock.lockNowDesc': 'Lock the main window immediately (sessions keep running)',
+  'settings.lock.lockNowDesc': 'Lock the main window immediately (sessions keep running, Ctrl+L)',
   'settings.lock.title': 'Locked',
   'settings.lock.screenDesc': 'Enter the lock password to unlock',
   'settings.lock.passwordPlaceholder': 'Password',