fix: Resolve host.docker.internal hostname resolution issue

- Change cache host from 'host.docker.internal' to empty string
- Allow act_runner to auto-detect the correct host IP address
- Update all runner configs: docker, heavy, light, security
- Improve troubleshooting scripts with host IP detection:
  - Linux/macOS: Use ip route, hostname -I, or ifconfig
  - Windows: Use Get-NetIPAddress PowerShell cmdlets
- Update documentation to reflect auto-detection approach

This resolves the 'getaddrinfo ENOTFOUND host.docker.internal' error
by using a more compatible approach that works across different
Docker setups and operating systems.

runners/fix-cache-issues.ps1

@@ -68,6 +68,35 @@ function Test-NetworkConnectivity {
     }
 }
 
+# Function to detect the correct host IP
+function Get-HostIP {
+    Write-Host "🔍 Detecting host IP address..." -ForegroundColor Cyan
+    
+    try {
+        # Try to get the IP address of the default gateway interface
+        $networkAdapters = Get-NetAdapter | Where-Object { $_.Status -eq "Up" -and $_.Name -notlike "*Loopback*" }
+        if ($networkAdapters) {
+            $ipConfig = Get-NetIPAddress -AddressFamily IPv4 | Where-Object { 
+                $_.InterfaceAlias -in $networkAdapters.Name -and $_.IPAddress -ne "127.0.0.1" 
+            } | Select-Object -First 1
+            
+            if ($ipConfig) {
+                $hostIP = $ipConfig.IPAddress
+                Write-Host "✅ Detected host IP: $hostIP" -ForegroundColor Green
+                return $hostIP
+            }
+        }
+        
+        # Fallback to localhost
+        Write-Host "⚠️  Could not detect host IP, using localhost" -ForegroundColor Yellow
+        return "127.0.0.1"
+    } catch {
+        Write-Host "⚠️  Error detecting host IP: $($_.Exception.Message)" -ForegroundColor Yellow
+        Write-Host "   Using localhost as fallback" -ForegroundColor Gray
+        return "127.0.0.1"
+    }
+}
+
 # Function to fix common cache issues
 function Fix-CacheIssues {
     Write-Host "🔧 Applying cache fixes..." -ForegroundColor Cyan
@@ -76,12 +105,15 @@ function Fix-CacheIssues {
     $cacheDir = "$env:USERPROFILE\.cache\actcache"
     New-Item -ItemType Directory -Path $cacheDir -Force | Out-Null
     
+    # Detect host IP
+    $hostIP = Get-HostIP
+    
     # Set proper environment variables
-    $env:ACTIONS_CACHE_URL = "http://host.docker.internal:44029/"
-    $env:ACTIONS_RUNTIME_URL = "http://host.docker.internal:44029/"
+    $env:ACTIONS_CACHE_URL = "http://${hostIP}:44029/"
+    $env:ACTIONS_RUNTIME_URL = "http://${hostIP}:44029/"
     
     Write-Host "✅ Cache directory created and configured" -ForegroundColor Green
-    Write-Host "✅ Environment variables set" -ForegroundColor Green
+    Write-Host "✅ Environment variables set with host IP: $hostIP" -ForegroundColor Green
 }
 
 # Function to restart cache service