zerotier-members: validate hex input to prevent ValueError

Add proper validation for network_id and identity parameters to ensure
they contain valid hexadecimal characters. Previously, non-hex input
would raise ValueError instead of the expected ClanError, bypassing
proper error handling.

pkgs/zerotier-members/zerotier-members.py

@@ -17,8 +17,16 @@ def compute_zerotier_ip(network_id: str, identity: str) -> ipaddress.IPv6Address
     if len(network_id) != 16:
         msg = f"network_id must be 16 characters long, got {network_id}"
         raise ClanError(msg)
+    try:
         nwid = int(network_id, 16)
+    except ValueError:
+        msg = f"network_id must be a valid hexadecimal string, got {network_id}"
+        raise ClanError(msg) from None
+    try:
         node_id = int(identity, 16)
+    except ValueError:
+        msg = f"identity must be a valid hexadecimal string, got {identity}"
+        raise ClanError(msg) from None
     addr_parts = bytearray(
         [
             0xFD,