vfs: move out of container

This package is not container-specific.

Signed-off-by: Ophestra <cat@gensokyo.uk>

vfs/mangle_test.go

@@ -0,0 +1,30 @@
+package vfs_test
+
+import (
+	"testing"
+
+	"hakurei.app/vfs"
+)
+
+func TestUnmangle(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		want   string
+		sample string
+	}{
+		{`\, `, `\134\054\040`},
+		{`(10) source -- maybe empty string`, `(10)\040source\040--\040maybe empty string`},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.want, func(t *testing.T) {
+			t.Parallel()
+			got := vfs.Unmangle(tc.sample)
+			if got != tc.want {
+				t.Errorf("Unmangle: %q, want %q",
+					got, tc.want)
+			}
+		})
+	}
+}