feat: Complete DOS machine deployment verification and AD2-NAS sync infrastructure

This checkpoint establishes verified deployment infrastructure for the Dataforth
DOS Update System with proper file synchronization and documentation.

## Key Changes

### TS-4R Backup and Analysis
- Backed up complete TS-4R machine to D:\ClaudeTools\backups\TS-4R\
- Analyzed MENUX.EXE startup menu system (758-line QuickBasic program)
- Documented complete startup sequence: AUTOEXEC.BAT → STARTNET.BAT → MENUX.EXE
- Found MENUX.BAS source code (Feb 2008 version) from KEPCO ABC software archive

### AD2-NAS Sync Infrastructure Fixes
- Created junction: COMMON → _COMMON (single source of truth for software updates)
- Verified bidirectional sync logic prevents data backflow:
  * Test data: DOS → NAS → AD2 → Database (one-way, deleted from NAS)
  * Program updates: AD2 → NAS → DOS (one-way, files remain on AD2)
- Manually deployed correct BAT file versions to NAS after sync connection issues
- Verified all 9 BAT files deployed correctly (5.1KB-8.8KB each)

### Deployment Scripts Created
- check-junction.ps1: Verify COMMON/\_COMMON junction status
- compare-common-folders.ps1: Compare folder contents
- deploy-correct-bat-files.ps1: Deploy BAT files from local to AD2
- fix-common-junction.ps1: Create COMMON → _COMMON junction
- verify-bat-deployment.ps1: Verify file versions on AD2
- manual-push-to-nas.sh: Manual BAT file deployment to NAS
- read-sync-script.ps1: Read Sync-FromNAS.ps1 from AD2
- search-menux-ad2.ps1: Search for MENUX source files

### Documentation Updates
- Updated all deployment guides with MENUX startup sequence
- Added startup flow to credentials.md and session logs
- Documented junction requirement for COMMON/\_COMMON
- Added data flow verification confirming unidirectional sync

## Technical Details

**Files Deployed to NAS (2026-01-20 09:01-09:02):**
- UPDATE.BAT (5,181 bytes) - Machine backup utility
- DEPLOY.BAT (5,579 bytes) - One-time deployment installer
- NWTOC.BAT (6,305 bytes) - Network to Computer updates
- CTONW.BAT (7,831 bytes) - Computer to Network uploads
- CTONWTXT.BAT (1,504 bytes) - Text file version
- CHECKUPD.BAT (6,495 bytes) - Check for updates
- STAGE.BAT (8,794 bytes) - Stage system files
- REBOOT.BAT (5,099 bytes) - Apply staged updates
- AUTOEXEC.BAT (2,211 bytes) - DOS startup configuration

**Sync Logic Verified:**
- PULL: /data/test/TS-*/LOGS/*.DAT copied to AD2, then deleted from NAS
- PUSH: C:\Shares\test\_COMMON\ProdSW\* copied to /data/test/COMMON/ProdSW/
- No reverse flow in either direction (test data never returns to DOS)

**Junction Created:**
- Target: C:\Shares\test\COMMON → C:\Shares\test\_COMMON
- Eliminates duplicate file maintenance
- Backup saved to C:\Shares\test\COMMON.backup

## Files Modified
- DOS_DEPLOYMENT_GUIDE.md: Added automatic startup sequence
- docs/DEPLOYMENT_GUIDE.md: Updated post-reboot expectations
- docs/ENGINEER_HOWTO_GUIDE.md: Added MENUX menu loading step
- credentials.md: Documented startup sequence and MENUX interface
- session-logs/2026-01-19-session.md: Added startup documentation

## Files Added
- 8 PowerShell deployment/verification scripts
- 3 HTML documentation exports
- TS-4R complete backup (not committed to git)

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

check-sync-status.ps1

@@ -1,38 +1,19 @@
-# Check if sync is running and show recent log output
-$password = ConvertTo-SecureString "Paper123!@#" -AsPlainText -Force
-$cred = New-Object System.Management.Automation.PSCredential("INTRANET\sysadmin", $password)
+$password = ConvertTo-SecureString 'Paper123!@#' -AsPlainText -Force
+$cred = New-Object System.Management.Automation.PSCredential('INTRANET\sysadmin', $password)
 
 Invoke-Command -ComputerName 192.168.0.6 -Credential $cred -ScriptBlock {
-    Write-Host "=== Sync Status Check ===" -ForegroundColor Cyan
-    Write-Host ""
-
-    # Check for running PowerShell processes with Sync-FromNAS
-    $syncProcesses = Get-Process powershell -ErrorAction SilentlyContinue | Where-Object {
-        $_.CommandLine -like "*Sync-FromNAS*"
-    }
-
-    if ($syncProcesses) {
-        Write-Host "[RUNNING] Sync process(es) active:" -ForegroundColor Yellow
-        $syncProcesses | ForEach-Object {
-            Write-Host "  PID $($_.Id) - Started: $($_.StartTime)" -ForegroundColor Gray
-        }
+    Write-Host "=== Sync Status File ===" -ForegroundColor Cyan
+    if (Test-Path "C:\Shares\test\_SYNC_STATUS.txt") {
+        Get-Content "C:\Shares\test\_SYNC_STATUS.txt"
     } else {
-        Write-Host "[IDLE] No sync processes running" -ForegroundColor Green
+        Write-Host "Status file not found" -ForegroundColor Red
     }
-
+    
     Write-Host ""
-    Write-Host "Recent log output (last 30 lines):" -ForegroundColor Cyan
-    Write-Host "=" * 80 -ForegroundColor Gray
-
-    Get-Content "C:\Shares\test\scripts\sync-from-nas.log" -Tail 30 | ForEach-Object {
-        if ($_ -match "ERROR|error") {
-            Write-Host $_ -ForegroundColor Red
-        } elseif ($_ -match "Pushed|Pulled") {
-            Write-Host $_ -ForegroundColor Green
-        } elseif ($_ -match "Starting|Complete") {
-            Write-Host $_ -ForegroundColor Cyan
-        } else {
-            Write-Host $_ -ForegroundColor Gray
-        }
+    Write-Host "=== Last 30 lines of Sync Log ===" -ForegroundColor Cyan
+    if (Test-Path "C:\Shares\test\scripts\sync-from-nas.log") {
+        Get-Content "C:\Shares\test\scripts\sync-from-nas.log" | Select-Object -Last 30
+    } else {
+        Write-Host "Log file not found" -ForegroundColor Red
     }
 }