Add Fit to Screen mode to Live view grid

Adds a toggle button to the Live view toolbar that automatically arranges
all cameras to fit within the viewport without scrolling. Uses a brute-force
algorithm to find the optimal number of columns that maximizes camera size
while keeping all cameras visible. State persists via IndexedDB.

https://claude.ai/code/session_01Cu7YDRKZrYX3sBs6g9w2dy

web/public/locales/en/views/live.json

@@ -174,6 +174,10 @@
     },
     "exitEdit": "Exit Editing"
   },
+  "fitToScreen": {
+    "enable": "Fit All Cameras to Screen",
+    "disable": "Disable Fit to Screen"
+  },
   "noCameras": {
     "title": "No Cameras Configured",
     "description": "Get started by connecting a camera to Frigate.",