Start the UI copy and button consistency pass

Add the screen/copy/button inventory and canonical terminology, standardize
inspection/wand admit-refuse hints, name the review action Return to menu, and
move radio action/hold/status labels into the string table. Headless 250/250,
Python 97/97, docs check OK.

content/strings.en.json

@@ -100,5 +100,13 @@
   "tutorial.radio": "Open the assistance radio and submit a short report.",
   "tutorial.review": "Finish the shift and review what happened.",
   "tutorial.completed": "Tutorial complete.",
+  "ui.inspect_actions": "A = admit · D = refuse entry",
+  "ui.wand_actions": "A = admit · D = refuse entry",
+  "ui.radio_send_assist": "Send request",
+  "ui.radio_send_emergency": "Send emergency",
+  "ui.radio_hold_hint": "Hold the button for %.1fs",
+  "ui.radio_cancelled": "Call cancelled — hold the button.",
+  "ui.radio_holding": "Holding… %.0f%%",
+  "ui.review_return_menu": "Return to menu",
   "tutorial.skipped": "Tutorial skipped."
 }