Add missing IIS configuration properties to global config

## Bug Fix

### Problem
IIS configuration failed with error:
```
[INSTALLATION FAILED] Cannot validate argument on parameter 'Name'.
The argument is null. Provide a valid value for the argument, and then try running the command again.
at Install-BackendFirstTime, line 643
```

The error occurred at line 643:
```powershell
Remove-WebAppPool -Name $Config.IISAppPoolName -ErrorAction SilentlyContinue
```

### Root Cause
Global configuration was missing IIS-related properties used in the IIS setup section:
- `$Config.IISAppPoolName` - used for Application Pool name (line 643, 646, 647)
- `$Config.IISSiteName` - used for IIS Site name (line 651, 653, 657)
- `$Config.IISAppName` - used for Web Application name (line 651, 653, 656)

When the script tried to use these null values, PowerShell validation failed.

### Solution
Added IIS configuration properties to `$script:Config` hashtable (lines 81-84):

```powershell
# IIS Configuration
IISSiteName = "Default Web Site"
IISAppName = "roa2web"
IISAppPoolName = "ROA2WEB-AppPool"
```

### Impact
- IIS Application Pool creation now works correctly
- Web Application is created under "Default Web Site" with path "/roa2web"
- Frontend files are served through IIS with proper app pool isolation

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

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

deployment/windows/scripts/ROA2WEB-Console.ps1

@@ -78,6 +78,11 @@ $script:Config = @{
     # Frontend
     FrontendPath = "C:\inetpub\wwwroot\roa2web\frontend"
 
+    # IIS Configuration
+    IISSiteName = "Default Web Site"
+    IISAppName = "roa2web"
+    IISAppPoolName = "ROA2WEB-AppPool"
+
     # Telegram Bot
     TelegramBotPath = "C:\inetpub\wwwroot\roa2web\telegram-bot"
     TelegramBotServiceName = "ROA2WEB-TelegramBot"