🐛(makefile) Windows compatibility fix for Docker volume mounting

On Windows systems, Docker volume paths starting
with a single / can be interpreted incorrectly
by the Docker daemon. The double slash (//) helps
Docker on Windows properly interpret the path as
an absolute path within the container, ensuring
that the working directory is correctly set
when running mail-related yarn commands.

CHANGELOG.md

@@ -18,6 +18,11 @@ and this project adheres to
   - #1244
   - #1270
 
+### Fixed
+
+- 🐛(makefile) Windows compatibility fix for Docker volume mounting #1264
+
+
 ## [3.5.0] - 2025-07-31
 
 ### Added