fix(printers): cam wall — offline tile chip + don't kill shared

streams when one viewer closes

1) Offline tiles now show OFF (not LIVE)
   CameraWall.modeByPrinter assigned 'live' to any visible printer
   without considering status.connected, so a disconnected X1C wasted
   a live-budget slot AND rendered the red LIVE chip on top of the
   WifiOff placeholder. Disconnected printers now map to 'paused' and
   don't decrement liveBudget — the existing WifiOff + Off chip
   rendering takes over.

2) /camera/stop no longer kills other viewers' streams
   The cam-wall tile, EmbeddedCameraViewer, and the /camera/:id popup
   all subscribe to the same fan-out broadcaster for a printer.
   /camera/stop used to unconditionally shutdown_broadcaster() + kill
   every ffmpeg process for the printer, so closing the embedded viewer
   while the cam-wall tile of the same printer was live force-killed
   the source the tile was pulling from — the tile's <img> errored.

   New get_subscriber_count(key) accessor in camera_fanout.py exposes
   the broadcaster's subscriber list length. /camera/stop now reads
   that first; when >= 1 subscriber is still attached, return
   {stopped: 0, skipped: true} and leave the broadcaster + ffmpeg
   processes alone. The leaving viewer's HTTP teardown still runs the
   natural iter_subscriber.finally -> unsubscribe path, so its slot is
   released; the broadcaster keeps serving the other viewers. Single-
   viewer close still hits the immediate force-teardown (count is 0).

frontend/scripts/check-i18n-parity.mjs

@@ -207,6 +207,7 @@ const FR_COGNATES = [
   'Cancelling upload...', 'Backup in progress...', 'Searching directory...',
   'EC984C,#6CD4BC,A66EB9,D87694',
   'Proxy', 'Navigation', 'Budget', 'Commit', 'Designer',
+  'Compact',  // cam-wall status overlay mode — same word in French
   'ntfy, Pushover, Discord, etc.',
   '{{filament}} @ {{temp}}°C',  // drying badge: filament code + universal °C
 ];
@@ -237,6 +238,7 @@ const IT_COGNATES = [
   'Hex: #{{hex}}',
   'EC984C,#6CD4BC,A66EB9,D87694',
   'Proxy', 'Designer',
+  'Off',  // cam-wall status overlay mode — common loanword in Italian UI
   '{{filament}} @ {{temp}}°C',  // drying badge: filament code + universal °C
 ];