feat: update dependencies and improve caching mechanism

- Added Prometheus client library for metrics collection.
- Refactored garbage collection strategy from random deletion to LRU (Least Recently Used) deletion.
- Introduced per-key locking in cache to prevent race conditions.
- Enhanced logging with structured log messages for cache hits and misses.
- Implemented a retry mechanism for upstream requests with exponential backoff.
- Updated Go modules and indirect dependencies for better compatibility and performance.
- Removed unused sync filesystem implementation.
- Added version initialization to ensure a default version string.

steamcache/logger/logger.go

@@ -1,13 +1,7 @@
 package logger
 
 import (
-	"os"
-
 	"github.com/rs/zerolog"
 )
 
-func init() {
-	zerolog.SetGlobalLevel(zerolog.InfoLevel)
-}
-
-var Logger = zerolog.New(zerolog.ConsoleWriter{Out: os.Stderr}).With().Timestamp().Logger()
+var Logger zerolog.Logger