feat(station): allow slave nodes to run without monitors

Make monitors optional so slave nodes can boot and play audio in terminal-only mode, while still using the monitor UI automatically when one is present.

station_broadcast.lua

@@ -2,7 +2,7 @@
 -- ============================================================================
 -- 1. Configuration & Constants
 -- ============================================================================
-local APP_VERSION_TEXT = "v1.0.8"
+local APP_VERSION_TEXT = "v1.0.9"
 
 local CONFIG = {
     CLOUD_URL = "ws://stabadmin.fse-media.group",
@@ -38,6 +38,7 @@ local State = {
     stationPlatform = "1",
     stationIdentityMode = "auto",
     hasStationPeripheral = false,
+    hasPrimaryMonitor = false,
     registered = false,
     stationList = {}, 
     currentTrain = nil,
@@ -67,10 +68,14 @@ function Peripherals.init()
     end
     -- Monitors
     local monitors = { peripheral.find("monitor") }
-    if #monitors == 0 then error("At least one monitor is required") end
-    -- Assign monitors
-    Peripherals.primaryMonitor = monitors[1]
-    Peripherals.primaryMonitor.setTextScale(0.5)
+    if #monitors > 0 then
+        Peripherals.primaryMonitor = monitors[1]
+        Peripherals.primaryMonitor.setTextScale(0.5)
+        State.hasPrimaryMonitor = true
+    else
+        Peripherals.primaryMonitor = nil
+        State.hasPrimaryMonitor = false
+    end
     -- Speakers
     Peripherals.speakers = { peripheral.find("speaker") }
 end
@@ -1691,6 +1696,7 @@ local Display = {}
 
 function Display.render()
     local mon = Peripherals.primaryMonitor
+    if not mon then return end
     local w, h = mon.getSize()
     mon.clear()
     mon.setCursorPos(1,1)
@@ -1831,7 +1837,7 @@ local Input = {}
 
 function Input.listener()
     Utils.log("DEBUG", "Input listener started")
-    local monitorName = peripheral.getName(Peripherals.primaryMonitor)
+    local monitorName = Peripherals.primaryMonitor and peripheral.getName(Peripherals.primaryMonitor) or nil
     
     while true do
         local event, param1, param2, param3 = os.pullEvent()
@@ -1952,6 +1958,11 @@ else
     Utils.log("WARN", "No train station peripheral on back; using manual slave mode")
     Utils.log("INFO", "Edit " .. CONFIG.STATION_IDENTITY_FILE .. " to set station_code/station_platform")
 end
+if Peripherals.primaryMonitor then
+    Utils.log("INFO", "Primary monitor detected")
+else
+    Utils.log("WARN", "No monitor detected; running in terminal-only mode")
+end
 
 parallel.waitForAny(
     function()