fix: Remove all non-DOS 6.22 commands from batch files

Critical compatibility fixes - DOS 6.22 does not support many Windows
batch file features. Removed all incompatible commands and replaced
with DOS 6.22 compatible alternatives.

Issues Fixed:

1. DEPLOY.BAT - Removed SET /P (interactive input)
   - Changed from: SET /P MACHINE=Machine name:
   - Changed to: SET MACHINE=%1 (command-line parameter)
   - Usage: DEPLOY.BAT TS-4R
   - DOS 6.22 does not support SET /P

2. CHECKUPD.BAT - Removed SET /A (arithmetic) and GOTO :EOF
   - Removed 6 instances of SET /A counter arithmetic
   - Replaced numeric counters with flag variables
   - Changed from: SET /A COMMON=COMMON+1
   - Changed to: SET COMMON=FOUND
   - Replaced GOTO :EOF with actual labels
   - Changed display from counts to status messages

3. STAGE.BAT - Removed FOR /F (file parsing)
   - Changed from: FOR /F "skip=1 delims=" %%L IN (...) DO
   - Changed to: TYPE C:\AUTOEXEC.BAT >> C:\AUTOEXEC.TMP
   - DOS 6.22 only supports simple FOR loops

Created check-dos-compatibility.ps1:
- Automated scanner for DOS 6.22 incompatible commands
- Checks for: SET /P, SET /A, IF /I, FOR /F, FOR /L, FOR /R,
  GOTO :EOF, %COMPUTERNAME%, &&, ||, START, invalid NUL usage
- Scans all BAT files and reports line numbers
- Essential for preventing future compatibility issues

Verification:
- All files maintain CRLF line terminators
- All commands tested for DOS 6.22 compatibility
- No SET /A, SET /P, FOR /F, GOTO :EOF remaining
- CHOICE commands retained (CHOICE.COM exists in DOS 6.22)

Impact:
- DEPLOY.BAT now requires parameter: DEPLOY.BAT TS-4R
- CHECKUPD.BAT shows "Updates available" vs exact counts
- STAGE.BAT copies all AUTOEXEC lines (duplicate @ECHO OFF harmless)

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

check-dos-compatibility.ps1

@@ -0,0 +1,69 @@
+# Comprehensive DOS 6.22 compatibility checker
+# Scans all BAT files for incompatible commands
+
+$BATFiles = Get-ChildItem *.BAT | Where-Object { $_.Name -notlike "*_FROM_*" -and $_.Name -notlike "*_TEST*" -and $_.Name -notlike "*_VERIFY*" -and $_.Name -notlike "*_CHECK*" -and $_.Name -notlike "*_MONITOR*" }
+
+Write-Host "========================================" -ForegroundColor Red
+Write-Host "DOS 6.22 COMPATIBILITY CHECK" -ForegroundColor Red
+Write-Host "========================================" -ForegroundColor Red
+Write-Host ""
+
+$TotalIssues = 0
+
+# DOS 6.22 INCOMPATIBLE patterns
+$IncompatiblePatterns = @(
+    @{Pattern='SET\s+/P'; Description='SET /P (interactive input) - NOT in DOS 6.22'},
+    @{Pattern='SET\s+/A'; Description='SET /A (arithmetic) - NOT in DOS 6.22'},
+    @{Pattern='IF\s+/I'; Description='IF /I (case-insensitive) - NOT in DOS 6.22'},
+    @{Pattern='FOR\s+/F'; Description='FOR /F (parse files) - NOT in DOS 6.22'},
+    @{Pattern='FOR\s+/L'; Description='FOR /L (loop) - NOT in DOS 6.22'},
+    @{Pattern='FOR\s+/D'; Description='FOR /D (directories) - NOT in DOS 6.22'},
+    @{Pattern='FOR\s+/R'; Description='FOR /R (recursive) - NOT in DOS 6.22'},
+    @{Pattern='GOTO\s+:EOF'; Description='GOTO :EOF - NOT in DOS 6.22 (use GOTO END)'},
+    @{Pattern='%COMPUTERNAME%'; Description='%COMPUTERNAME% - NOT in DOS 6.22'},
+    @{Pattern='%USERNAME%'; Description='%USERNAME% - NOT in DOS 6.22'},
+    @{Pattern='%USERPROFILE%'; Description='%USERPROFILE% - NOT in DOS 6.22'},
+    @{Pattern='&&'; Description='&& operator - NOT in DOS 6.22'},
+    @{Pattern='\|\|'; Description='|| operator - NOT in DOS 6.22'},
+    @{Pattern='\\NUL(?!\s|$)'; Description='\NUL as filename - INVALID (use \*.* for directory test)'},
+    @{Pattern='CHOICE\s+/[A-Z]'; Description='CHOICE with options - Check if CHOICE.COM available'},
+    @{Pattern='START\s+'; Description='START command - NOT in DOS 6.22'}
+)
+
+foreach ($File in $BATFiles) {
+    Write-Host "Checking: $($File.Name)" -ForegroundColor Cyan
+
+    $Content = Get-Content $File.FullName
+    $FileIssues = 0
+
+    foreach ($Pattern in $IncompatiblePatterns) {
+        $LineNum = 0
+        foreach ($Line in $Content) {
+            $LineNum++
+            if ($Line -match $Pattern.Pattern) {
+                if ($FileIssues -eq 0) {
+                    Write-Host ""
+                }
+                Write-Host "  [ERROR] Line $LineNum : $($Pattern.Description)" -ForegroundColor Red
+                Write-Host "    > $Line" -ForegroundColor Yellow
+                $FileIssues++
+                $TotalIssues++
+            }
+        }
+    }
+
+    if ($FileIssues -eq 0) {
+        Write-Host "  [OK] No incompatibilities found" -ForegroundColor Green
+    }
+
+    Write-Host ""
+}
+
+Write-Host "========================================" -ForegroundColor Red
+Write-Host "TOTAL ISSUES FOUND: $TotalIssues" -ForegroundColor Red
+Write-Host "========================================" -ForegroundColor Red
+
+if ($TotalIssues -gt 0) {
+    Write-Host ""
+    Write-Host "ACTION REQUIRED: Fix all incompatibilities before deployment" -ForegroundColor Red
+}