fix: pass client_address with CIDR mask to wg-peerctl on enable

Stripping /32 caused AllowedIPs without mask in wg0.conf.
wg-peerctl needs full CIDR notation for AllowedIPs to be correct.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

gui/app.py

@@ -564,7 +564,7 @@ def peer_enable(peer_id: int):
 
     name = item.get("name", "")
     pk = item.get("public_key", "")
-    addr = (item.get("client_address", "") or "").split("/")[0]  # strip /32 if present
+    addr = (item.get("client_address", "") or "")
     routes = item.get("advertised_routes", "") or ""
     psk = item.get("peer_psk", "") or ""
     if not (name and pk):