Standardize ASP filenames: remove underscores

Renamed 45 ASP files to follow lowercase concatenated naming convention:
- Direct handlers: save_machine_direct.asp -> savemachinedirect.asp
- USB files: checkin_usb.asp -> checkinusb.asp
- API files: api_usb.asp -> apiusb.asp
- Map files: network_map.asp -> networkmap.asp
- Printer files: printer_lookup.asp -> printerlookup.asp

Also:
- Updated 84+ internal references across all ASP and JS files
- Deleted 6 test/duplicate files (editmacine.asp, test_*.asp)
- Updated production migration guide with filename changes
- Added rename scripts for Linux (bash) and Windows (PowerShell)

refreshzabbixcache.asp

@@ -0,0 +1,60 @@
+<%
+' Background cache refresh endpoint
+' Called asynchronously to update cache without blocking users
+' DO NOT call this directly in browser - it's for internal async calls only
+
+Response.Buffer = True
+Response.ContentType = "text/plain"
+
+Dim hostIP, cacheKey
+hostIP = Request.QueryString("ip")
+
+' Validate IP parameter
+If hostIP = "" Then
+    Response.Write("Error: No IP specified")
+    Response.End
+End If
+
+' Include Zabbix functions
+%>
+<!--#include file="./includes/zabbix.asp"-->
+<%
+
+cacheKey = "zabbix_" & hostIP
+
+' Fetch fresh data from Zabbix
+Dim zabbixConnected, pingStatus, tonerJSON, resultData(2)
+
+On Error Resume Next
+zabbixConnected = ZabbixLogin()
+
+If zabbixConnected = "1" Then
+    pingStatus = GetPrinterPingStatus(hostIP)
+    tonerJSON = GetPrinterTonerLevels(hostIP)
+Else
+    pingStatus = "-1"
+    tonerJSON = ""
+End If
+
+If Err.Number <> 0 Then
+    Response.Write("Error: " & Err.Description)
+    Application.Lock
+    Application(cacheKey & "_refreshing") = "false"
+    Application.Unlock
+    Response.End
+End If
+On Error Goto 0
+
+' Update cache with fresh data
+resultData(0) = zabbixConnected
+resultData(1) = pingStatus
+resultData(2) = tonerJSON
+
+Application.Lock
+Application(cacheKey) = resultData
+Application(cacheKey & "_time") = Now()
+Application(cacheKey & "_refreshing") = "false"
+Application.Unlock
+
+Response.Write("OK: Cache updated for " & hostIP & " at " & Now())
+%>