fix: restore speaker peripheral detection

Re-add speaker discovery during peripheral init so installed speakers are available for playback and log the detected count at startup.

station_broadcast.lua

@@ -120,6 +120,7 @@ function Peripherals.init()
         State.hasPrimaryMonitor = false
     end
 
+    Peripherals.speakers = { peripheral.find("speaker") }
 
     Peripherals.createTarget = peripheral.find("create_target")
     if Peripherals.createTarget then
@@ -2971,6 +2972,11 @@ if Peripherals.primaryMonitor then
 else
     Utils.log("WARN", "No monitor detected; running in terminal-only mode")
 end
+if Peripherals.speakers and #Peripherals.speakers > 0 then
+    Utils.log("INFO", "Speaker detected x" .. tostring(#Peripherals.speakers))
+else
+    Utils.log("WARN", "No speaker detected")
+end
 
 parallel.waitForAny(
     function()