implement alternative match-making approach with Lua scripts in Redis

main-server/app/controllers/api/matchmaking_controller.rb

@@ -1,19 +1,6 @@
 class Api::MatchmakingController < ApplicationController
-  def create
-    result = MatchmakingService.find_match(current_user.id)
-
-    if result
-      render json: {
-        match_id: result[:match_id],
-        game_token: result[:game_token],
-        game_server: result[:game_server],
-        players: result[:players]
-      }
-    else
-      render json: { error: "No opponent found. Try again." }, status: :request_timeout
-    end
-  end
-
+  # Explicit cancellation. Normally the search is cancelled automatically
+  # when the MatchmakingChannel subscription is closed.
   def destroy
     MatchmakingService.cancel(current_user.id)
     render json: { message: "Matchmaking cancelled" }