Fix: Use full path for 'net' command in Samba config reading

subprocess needs full path to executable when PATH is not set.
Use /usr/bin/net instead of 'net'.

Co-Authored-By: Patrick <patrick@perlbach24.de>

backend/services/shares.py

@@ -183,7 +183,7 @@ class SharesManager:
         """Read Samba global configuration from registry using 'net conf list'"""
         try:
             result = subprocess.run(
-                ['net', 'conf', 'list'],
+                ['/usr/bin/net', 'conf', 'list'],
                 capture_output=True,
                 text=True,
                 timeout=10