Adopt SearchSelect for device, platform, and play event game fields

- Parameterize SearchSelectWidget with a required options_resolver so
  each widget explicitly names its resolver instead of implicitly using
  _game_options
- Add autofocus support: SearchSelect forwards it to the search input,
  and SearchSelectWidget extracts it from Django's attrs dict
- Add _device_options and _platform_options resolvers (single pk__in
  queries, same pattern as _game_options)
- Add /api/devices/search and /api/platforms/search endpoints
- Switch PlayEventForm.game from plain Select to SearchSelectWidget
  (preserving autofocus), and use SingleGameChoiceField for correct labels
- Switch SessionForm.device to SearchSelectWidget
- Switch PurchaseForm.platform and GameForm.platform to SearchSelectWidget
- Wire ModuleScript("search_select.js") into add/edit playevent and
  add/edit game views

https://claude.ai/code/session_013fpJD54HxRgxRv2xzwXGNo

games/views/game.py

@@ -180,7 +180,7 @@ def add_game(request: HttpRequest) -> HttpResponse:
             ),
         ),
         title="Add New Game",
-        scripts=ModuleScript("add_game.js"),
+        scripts=ModuleScript("search_select.js") + ModuleScript("add_game.js"),
     )
 
 
@@ -332,7 +332,12 @@ def edit_game(request: HttpRequest, game_id: int) -> HttpResponse:
     if form.is_valid():
         form.save()
         return redirect("games:list_sessions")
-    return render_page(request, AddForm(form, request=request), title="Edit Game")
+    return render_page(
+        request,
+        AddForm(form, request=request),
+        title="Edit Game",
+        scripts=ModuleScript("search_select.js"),
+    )
 
 
 # --- view_game content builders -------------------------------------------