fix(builder): don't count Docker's init or the Steam client's own files as lost saves

Every container the node-agent starts gets /usr/sbin/docker-init, and SteamCMD
rewrites its own config.vdf on every run. Counted as files written outside the
volumes, they made every build look like it loses saves. A folder whose only
changes were logs no longer counts either, and a folder followed by a
same-named file (worlds, worlds.bak) is no longer taken for a file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/gbrgames/draft.go

@@ -336,9 +336,6 @@ func closestVar(name string, vars []string) string {
 	return best
 }
 
-// Files the Steam client, Proton and the OS write for themselves: not the game's data
-var outsideNoise = []string{"/Steam/logs/", "/.steam/", "/steamcmd/", "/.cache/", "/tmp/", "/.local/share/umu"}
-
 // savesOutsideVolumes turns first boot's "written outside the volumes" into a hard check: anything the
 // game itself wrote there (worlds or player lists under the user's home folder) is lost every time the
 // node recreates the container. A template passes once its startup command or settings point the game at
@@ -372,14 +369,8 @@ func outsideDirs(report *bootReport) []string {
 	}
 	dirs := map[string]bool{}
 	for _, c := range report.ContainerChanges {
-		_, p, _ := strings.Cut(c, " ")
-		noise := false
-		for _, n := range outsideNoise {
-			if strings.Contains(p, n) {
-				noise = true
-			}
-		}
-		if !noise && p != "" {
+		// A report saved by an older version can still list files that aren't the game's state
+		if _, p, _ := strings.Cut(c, " "); p != "" && !notGameState(p) {
 			dirs[path.Dir(p)] = true
 		}
 	}