Add experimental disclaimer for PowerShell installer

Users are now warned that the PowerShell installer is experimental
and WSL is recommended for reliable installation.

Changes:
- README: Added warning banner, changed WSL to "Recommended"
- PowerShell script: Added interactive warning at startup
- WordPress article: Added yellow warning box before Windows section

PowerShell installer now shows:
- Yellow warning about experimental status
- WSL command for reliable installation
- Prompt to press Ctrl+C to exit or Enter to continue

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

install-windows.ps1

@@ -77,6 +77,16 @@ function Show-Banner {
 ╚═══════════════════════════════════════════════════════════════╝
 
 "@ -ForegroundColor Cyan
+
+    # Show warning about experimental status
+    Write-Host ""
+    Write-Host "⚠️  WARNING: This PowerShell installer is EXPERIMENTAL and may have bugs." -ForegroundColor Yellow
+    Write-Host "   For reliable installation, we recommend using WSL instead:" -ForegroundColor Yellow
+    Write-Host "   wsl bash -c 'git clone https://github.rommark.dev/admin/SuperCharged-Claude-Code-Upgrade.git && cd SuperCharged-Claude-Code-Upgrade && ./supercharge.sh'" -ForegroundColor White
+    Write-Host ""
+    Write-Host "   Press Ctrl+C to exit and use WSL, or press Enter to continue..." -ForegroundColor Cyan
+    Read-Host
+    Write-Host ""
 }
 
 function Test-ClaudeCode {