Add integration tests and service management for SteamCache

- Introduced integration tests for SteamCache to validate caching behavior with real Steam URLs.
- Implemented a ServiceManager to manage service configurations, allowing for dynamic detection of services based on User-Agent.
- Updated cache key generation to include service prefixes, enhancing cache organization and retrieval.
- Enhanced the caching logic to support multiple services, starting with Steam and Epic Games.
- Improved .gitignore to exclude test cache files while retaining necessary structure.

vfs/disk/disk.go

@@ -184,7 +184,12 @@ func (d *DiskFS) init() {
 
 		d.mu.Lock()
 		// Extract key from sharded path: remove root and convert sharding back
-		relPath := strings.ReplaceAll(npath[len(d.root)+1:], "\\", "/")
+		// Handle both "./disk" and "disk" root paths
+		rootPath := d.root
+		if strings.HasPrefix(rootPath, "./") {
+			rootPath = rootPath[2:] // Remove "./" prefix
+		}
+		relPath := strings.ReplaceAll(npath[len(rootPath)+1:], "\\", "/")
 
 		// Extract the original key from the sharded path
 		k := d.extractKeyFromPath(relPath)