feat: enforce tiered storage reservations

internal/server/store/free_windows.go

@@ -0,0 +1,25 @@
+//go:build windows
+
+package store
+
+import (
+	"path/filepath"
+
+	"golang.org/x/sys/windows"
+)
+
+func filesystemFreeBytes(path string) (uint64, error) {
+	absolute, err := filepath.Abs(path)
+	if err != nil {
+		return 0, err
+	}
+	pointer, err := windows.UTF16PtrFromString(absolute)
+	if err != nil {
+		return 0, err
+	}
+	var available uint64
+	if err := windows.GetDiskFreeSpaceEx(pointer, &available, nil, nil); err != nil {
+		return 0, err
+	}
+	return available, nil
+}