Add RR3 Asset Extraction & Management System

Cross-Platform Scripts:
- extract_z_asset.sh: Linux/Unix single file extraction
- batch_extract_z_assets.sh: Linux/Unix batch extraction
- pack_z_asset.sh: Linux/Unix asset packing
- extract_z_asset.ps1: Windows PowerShell extraction

Server Integration:
- AssetExtractionService.cs: C# service for ZLIB extraction/packing
- AssetManagementController.cs: API endpoints for asset management
  - POST /api/AssetManagement/extract
  - POST /api/AssetManagement/pack
  - POST /api/AssetManagement/batch-extract
  - GET /api/AssetManagement/list
- Registered AssetExtractionService in Program.cs

Features:
- Extracts .z files (ZLIB compressed textures/data)
- Packs files to .z format with ZLIB compression
- Batch processing support
- Cross-platform (Windows/Linux/macOS)
- Server-side API for remote asset management
- Path traversal protection

Documentation:
- ASSET_EXTRACTION_GUIDE.md: Complete integration guide
- Tools/README.md: CLI tool documentation

Based on: Tankonline/Real-Racing-3-Texture-Extraction-Tool
Converted to cross-platform bash/PowerShell scripts + C# service

Ready for .pak asset extraction when files arrive from community

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Tools/extract_z_asset.ps1

@@ -0,0 +1,106 @@
+# RR3 Asset Extraction PowerShell Script
+# Extracts .z (ZLIB compressed) texture files from Real Racing 3
+
+param(
+    [Parameter(Mandatory=$true)]
+    [string]$InputFile,
+    
+    [Parameter(Mandatory=$false)]
+    [string]$OutputDir
+)
+
+Write-Host "════════════════════════════════════════════════════════════" -ForegroundColor Cyan
+Write-Host "   RR3 Asset Extraction Tool - Windows" -ForegroundColor Yellow
+Write-Host "════════════════════════════════════════════════════════════" -ForegroundColor Cyan
+Write-Host ""
+
+# Validate input
+if (-not (Test-Path $InputFile)) {
+    Write-Host "ERROR: Input file not found: $InputFile" -ForegroundColor Red
+    exit 1
+}
+
+# Default output dir
+if (-not $OutputDir) {
+    $OutputDir = Split-Path -Parent $InputFile
+}
+
+Write-Host "Input file: $InputFile" -ForegroundColor Green
+Write-Host "Output directory: $OutputDir" -ForegroundColor Green
+Write-Host ""
+
+# Create output directory
+New-Item -ItemType Directory -Path $OutputDir -Force | Out-Null
+
+# Read file
+Write-Host "Reading file..." -ForegroundColor Cyan
+$data = [System.IO.File]::ReadAllBytes($InputFile)
+
+$output = New-Object System.Collections.ArrayList
+$i = 0
+$found = 0
+
+Write-Host "Scanning for ZLIB blocks..." -ForegroundColor Cyan
+
+# Scan for zlib blocks (magic bytes 0x78 0x9C, 0xDA, or 0x01)
+while ($i -lt ($data.Length - 2)) {
+    if ($data[$i] -eq 0x78 -and ($data[$i+1] -eq 0x9C -or $data[$i+1] -eq 0xDA -or $data[$i+1] -eq 0x01)) {
+        try {
+            # Try to decompress from this position
+            $compressed = $data[$i..($data.Length-1)]
+            $decompressed = [System.IO.Compression.DeflateStream]::new(
+                [System.IO.MemoryStream]::new($compressed, 2, $compressed.Length - 2),
+                [System.IO.Compression.CompressionMode]::Decompress
+            )
+            
+            $ms = New-Object System.IO.MemoryStream
+            $decompressed.CopyTo($ms)
+            $decompressed.Close()
+            
+            $block = $ms.ToArray()
+            $ms.Close()
+            
+            if ($block.Length -gt 0) {
+                $output.AddRange($block)
+                Write-Host "  [+] Block $found at 0x$($i.ToString('X'))" -ForegroundColor Gray
+                $found++
+                $i += $block.Length
+                continue
+            }
+        } catch {
+            # Not a valid zlib block, continue
+        }
+    }
+    $i++
+}
+
+if ($found -eq 0) {
+    Write-Host "ERROR: No valid zlib blocks found!" -ForegroundColor Red
+    exit 1
+}
+
+# Get output filename
+$baseName = [System.IO.Path]::GetFileName($InputFile)
+if ($baseName.ToLower().EndsWith(".z")) {
+    $baseName = $baseName.Substring(0, $baseName.Length - 2)
+}
+
+$outputFile = Join-Path $OutputDir $baseName
+
+# Backup if exists
+if (Test-Path $outputFile) {
+    $bakFile = "$outputFile.bak"
+    if (-not (Test-Path $bakFile)) {
+        Move-Item $outputFile $bakFile
+        Write-Host "Backup created: $bakFile" -ForegroundColor Yellow
+    }
+}
+
+# Write output
+[System.IO.File]::WriteAllBytes($outputFile, $output.ToArray())
+
+Write-Host ""
+Write-Host "✅ Extraction complete!" -ForegroundColor Green
+Write-Host "Output: $outputFile" -ForegroundColor White
+Write-Host "Blocks found: $found" -ForegroundColor White
+Write-Host "Size: $($output.Count) bytes" -ForegroundColor White