Fix dualpath propagation, getShopfloorPCs filtering, USB management, and printer features

- Fix dualpath PC propagation direction (Equipment->PC) in api.asp and db_helpers.asp
- Fix early exit in CreatePCMachineRelationship preventing propagation
- Fix getShopfloorPCs to filter machinetypeid IN (33,34,35) instead of >= 33
- Fix getShopfloorPCs to show equipment numbers via GROUP_CONCAT subquery
- Add detailed PropagateDP logging for dualpath debugging
- Default "Show on Shopfloor Dashboard" checkbox to checked in addnotification.asp
- Add USB label batch printing, single USB labels, and USB history pages
- Add printer supplies tracking and toner report enhancements
- Add uptime map visualization page
- Add dashboard/lobby display SQL migration
- Update CLAUDE.md with IIS 401 workaround documentation
- Update TODO.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

includes/zabbix_all_supplies_cached.asp

@@ -1,54 +1,37 @@
 <%
 ' Cached Zabbix API wrapper for ALL supply levels (toner, ink, drums, maintenance kits, etc.)
+' Simplified caching - no background refresh, minimal locking
 %>
 <!--#include file="./zabbix_all_supplies.asp"-->
 <%
 
-' Cached function for all supply levels - returns data immediately, refreshes in background if stale
+' Cached function for all supply levels - simple 5-minute cache
 Function GetAllPrinterSuppliesCached(hostIP)
-    Dim cacheKey, cacheAge, forceRefresh
+    On Error Resume Next
+
+    Dim cacheKey, cacheTime, cacheAge, cachedData, forceRefresh
     cacheKey = "zabbix_all_supplies_" & hostIP
 
     ' Check if manual refresh was requested
     forceRefresh = (Request.QueryString("refresh") = "1" And Request.QueryString("ip") = hostIP)
 
-    If forceRefresh Then
-        ' Clear cache for manual refresh
-        Application.Lock
-        Application(cacheKey) = Empty
-        Application(cacheKey & "_time") = Empty
-        Application(cacheKey & "_refreshing") = "false"
-        Application.Unlock
-    End If
+    ' Check if valid cache exists (without locking)
+    If Not forceRefresh Then
+        cachedData = Application(cacheKey)
+        cacheTime = Application(cacheKey & "_time")
 
-    ' Check if cache exists
-    If Not IsEmpty(Application(cacheKey)) And Not forceRefresh Then
-        cacheAge = DateDiff("n", Application(cacheKey & "_time"), Now())
-
-        ' If cache is stale (>5 min) AND not already refreshing, trigger background update
-        If cacheAge >= 5 And Application(cacheKey & "_refreshing") <> "true" Then
-            ' Mark as refreshing
-            Application.Lock
-            Application(cacheKey & "_refreshing") = "true"
-            Application.Unlock
-
-            ' Trigger async background refresh (non-blocking)
-            On Error Resume Next
-            Dim http
-            Set http = Server.CreateObject("MSXML2.ServerXMLHTTP.6.0")
-            http.Open "GET", "http://localhost/refresh_all_supplies_cache.asp?ip=" & Server.URLEncode(hostIP), True
-            http.Send
-            Set http = Nothing
-            On Error Goto 0
+        If Not IsEmpty(cachedData) And Not IsEmpty(cacheTime) Then
+            cacheAge = DateDiff("n", cacheTime, Now())
+            If cacheAge < 5 Then
+                ' Cache is fresh, return it
+                GetAllPrinterSuppliesCached = cachedData
+                Exit Function
+            End If
         End If
-
-        ' Return cached data immediately
-        GetAllPrinterSuppliesCached = Application(cacheKey)
-        Exit Function
     End If
 
-    ' No cache exists - fetch initial data
-    Dim freshData, zabbixConnected, pingStatus, suppliesJSON
+    ' Cache miss or stale - fetch fresh data
+    Dim zabbixConnected, pingStatus, suppliesJSON
 
     zabbixConnected = ZabbixLogin()
 
@@ -66,13 +49,13 @@ Function GetAllPrinterSuppliesCached(hostIP)
     resultData(1) = pingStatus
     resultData(2) = suppliesJSON
 
-    ' Cache the result
+    ' Cache the result (brief lock)
     Application.Lock
     Application(cacheKey) = resultData
     Application(cacheKey & "_time") = Now()
-    Application(cacheKey & "_refreshing") = "false"
     Application.Unlock
 
+    On Error Goto 0
     GetAllPrinterSuppliesCached = resultData
 End Function