refactor(gate): streamline gate installers and support multi-station codes via splitCsv

installer_bi.lua

@@ -97,7 +97,7 @@ term.setCursorPos(1, 1)
 print("Bidirectional Ticket Gate Installer")
 print("")
 
-local stationCode = trim(prompt("Station code: "))
+local stationCode = trim(prompt("Station code(s) [comma or / separated]: "))
 if #stationCode == 0 then
   print("No station code provided.")
   return
@@ -110,16 +110,17 @@ local backRaw = prompt("Back mode (entry/exit): ")
 local frontMode = normalizeMode(frontRaw)
 local backMode = normalizeMode(backRaw)
 
+local parsedCodes = splitCsv(stationCode)
 local cfg = {
-  station_codes = { stationCode },
-  station_code = stationCode,
+  station_codes = parsedCodes,
+  station_code = parsedCodes[1] or stationCode,
   side_modes = {
     front = frontMode,
     back = backMode,
   },
   side_station_codes = {
-    front = stationCode,
-    back = stationCode,
+    front = parsedCodes[1] or stationCode,
+    back = parsedCodes[1] or stationCode,
   }
 }
 local okCfg, cfgJson = pcall(textutils.serializeJSON, cfg)