Standardize UI consistency across ShopDB pages

Security fixes:
- Add HTMLEncode to displaysubnets.asp output
- Add HTMLEncode to displayapplications.asp URL attributes

Icon standardization:
- Use zmdi-plus-circle for all Add buttons (displaypcs, pcs, pclist, computers, listpcs)
- Use zmdi-edit for all Edit tab icons (displayapplication, displayprinter, displaysubnet, displaydevice)
- Replace icon-note with zmdi icons throughout

Layout consistency:
- Standardize title row margin-bottom to 15px across all pages
- Add table-hover class to all data tables
- Fix editpc.asp title from "Edit Equipment" to "Edit PC"
- Fix editpc.asp back link to point to displaypcs.asp

Terminology:
- Change "Make" to "Vendor" in displayprinters.asp
- Standardize Back button text to "Back to [Page]" format

Generated with [Claude Code](https://claude.com/claude-code)

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

displaymachines.asp

@@ -33,7 +33,7 @@
           <div class="card">
             <div class="card-body">
               <div style="margin-bottom:15px;">
-                <div style="display:flex; justify-content:space-between; align-items:center; margin-bottom:10px;">
+                <div style="display:flex; justify-content:space-between; align-items:center; margin-bottom:15px;">
                   <h5 class="card-title" style="margin:0;"><a href="./machine_map.asp" target="_blank"><i class='zmdi zmdi-map' title='Show Machine Map'></i></a>&nbsp;&nbsp;&nbsp;&nbsp;Machines</h5>
                   <div>
                     <a href="./addmachine.asp" class="btn btn-primary">