Update SystemTester.bat

New Features Added
1. Tool Integrity Verification Function
Added Test-ToolIntegrity() function that:

Checks 8 key tools for minimum expected file sizes
Detects suspiciously small files (corrupted downloads)
Validates .exe extension
Has optional digital signature verification (commented out for speed)
Provides launcher-aware recommendations for re-download
Asks user permission to continue if issues found

2. Integrated into Initialize-Environment
The function now:

Checks for folder existence
Counts available tools
Runs integrity verification (new!)
Only proceeds if all checks pass

3. Launcher Awareness Working

Detects $env:SYSTESTER_LAUNCHER variable
Provides contextual messages based on how script was launched
Guides users to Option 6 when appropriate

Author: Pnwcomputers