feat: add GPU shader cache cleanup (NVIDIA, AMD, Intel, DirectX)

Add Clear-GPUShaderCaches function to clean GPU shader caches:
- NVIDIA: DXCache, GLCache, NV_Cache
- AMD: DXCache, GLCache, VkCache
- Intel: ShaderCache
- DirectX: D3DSCache, DirectX Shader Cache
- Vulkan: VulkanCache (pipeline cache)

These caches can grow to 10GB+ and are safe to delete.
They will be rebuilt automatically when needed.

Integrated into main clean.ps1 workflow.

bin/clean.ps1

@@ -230,6 +230,9 @@ function Start-Cleanup {
         # Browser caches
         Clear-BrowserCaches
 
+        # GPU shader caches (NVIDIA, AMD, Intel, DirectX)
+        Clear-GPUShaderCaches
+
         # Application caches
         Clear-AppCaches
 

lib/clean/caches.ps1

@@ -337,6 +337,79 @@ function Clear-DotNetCaches {
     # Assembly cache (don't touch - managed by CLR)
 }
 
+# ============================================================================
+# GPU Shader Caches
+# ============================================================================
+
+function Clear-GPUShaderCaches {
+    <#
+    .SYNOPSIS
+        Clean GPU shader caches (NVIDIA, AMD, Intel, DirectX)
+    .DESCRIPTION
+        GPU drivers cache compiled shaders to improve game/app load times.
+        These caches can grow very large (10GB+) and are safe to delete.
+        They will be rebuilt automatically when needed.
+    #>
+    
+    Start-Section "GPU shader caches"
+    
+    # NVIDIA shader caches
+    $nvidiaCachePaths = @(
+        "$env:LOCALAPPDATA\NVIDIA\DXCache"
+        "$env:LOCALAPPDATA\NVIDIA\GLCache"
+        "$env:LOCALAPPDATA\NVIDIA Corporation\NV_Cache"
+        "$env:TEMP\NVIDIA Corporation\NV_Cache"
+    )
+    foreach ($path in $nvidiaCachePaths) {
+        if (Test-Path $path) {
+            Clear-DirectoryContents -Path $path -Description "NVIDIA shader cache"
+        }
+    }
+    
+    # AMD shader caches
+    $amdCachePaths = @(
+        "$env:LOCALAPPDATA\AMD\DXCache"
+        "$env:LOCALAPPDATA\AMD\GLCache"
+        "$env:LOCALAPPDATA\AMD\VkCache"
+    )
+    foreach ($path in $amdCachePaths) {
+        if (Test-Path $path) {
+            Clear-DirectoryContents -Path $path -Description "AMD shader cache"
+        }
+    }
+    
+    # Intel shader caches
+    $intelCachePaths = @(
+        "$env:LOCALAPPDATA\Intel\ShaderCache"
+        "$env:APPDATA\Intel\ShaderCache"
+    )
+    foreach ($path in $intelCachePaths) {
+        if (Test-Path $path) {
+            Clear-DirectoryContents -Path $path -Description "Intel shader cache"
+        }
+    }
+    
+    # DirectX shader cache (system-wide)
+    $dxCachePath = "$env:LOCALAPPDATA\D3DSCache"
+    if (Test-Path $dxCachePath) {
+        Clear-DirectoryContents -Path $dxCachePath -Description "DirectX shader cache"
+    }
+    
+    # DirectX pipeline cache
+    $dxPipelinePath = "$env:LOCALAPPDATA\Microsoft\DirectX Shader Cache"
+    if (Test-Path $dxPipelinePath) {
+        Clear-DirectoryContents -Path $dxPipelinePath -Description "DirectX pipeline cache"
+    }
+    
+    # Vulkan pipeline cache (common location)
+    $vulkanCachePath = "$env:LOCALAPPDATA\VulkanCache"
+    if (Test-Path $vulkanCachePath) {
+        Clear-DirectoryContents -Path $vulkanCachePath -Description "Vulkan pipeline cache"
+    }
+    
+    Stop-Section
+}
+
 # ============================================================================
 # Main Cache Cleanup Function
 # ============================================================================
@@ -349,7 +422,8 @@ function Invoke-CacheCleanup {
     param(
         [switch]$IncludeWindowsUpdate,
         [switch]$IncludeBrowsers,
-        [switch]$IncludeApps
+        [switch]$IncludeApps,
+        [switch]$IncludeGPU
     )
     
     Start-Section "System caches"
@@ -368,6 +442,11 @@ function Invoke-CacheCleanup {
     
     Stop-Section
     
+    # GPU shader caches
+    if ($IncludeGPU) {
+        Clear-GPUShaderCaches
+    }
+    
     # Browser caches
     if ($IncludeBrowsers) {
         Clear-BrowserCaches