feat(place): final end time + destruction wave

polylan_submitter/place/api.py

@@ -35,10 +35,14 @@ HEADER_FORMAT = "<HH"
 @decorate_view(require_game_enabled(path="place"))
 def canvas(request: HttpRequest, event_path: str):
     """The one-time full-grid load. Every placement after that arrives as a
-    single websocket message, never a re-fetch."""
+    single websocket message, never a re-fetch. Once placement is over the
+    board is shown wiped (Redis keeps the real final board, see tasks.py)."""
     place_settings = PlaceSettings.current(request.event)
     header = struct.pack(HEADER_FORMAT, place_settings.width, place_settings.height)
-    pixels = read_canvas(event_path, place_settings.width, place_settings.height)
+    if place_settings.placement_ended:
+        pixels = bytes(place_settings.width * place_settings.height)
+    else:
+        pixels = read_canvas(event_path, place_settings.width, place_settings.height)
     return HttpResponse(header + pixels, content_type="application/octet-stream")