fix: name and version from system_information; a CARP address on its MASTER's interface

get_facts read hostname and version from /api/core/system/status, which on
OPNsense 26.7 carries neither: every firewall read as nameless and "unknown",
and netOrk kept naming one by its address. /api/diagnostics/system/system_information
has both (name is the FQDN, versions[0] "OPNsense 26.7.7-amd64"). The status
answer still counts where the new one gives nothing.

get_interfaces_ip listed each interface's primary address only, so a CARP address
never showed as the holder's. It now lists an address bound to a VHID on the node
that is MASTER for it, and leaves it off a BACKUP -- as keepalived puts the address
on the master alone. netOrk's VIP badge sits on that interface (netOrk #1121).

README.md

@@ -71,9 +71,9 @@ arguments.
 
 | Getter | Status | OPNsense API Endpoint |
 |---|---|---|
-| `get_facts` | ✅ | `GET /api/core/system/status` |
+| `get_facts` | ✅ | `GET /api/diagnostics/system/system_information` (name, version) + `GET /api/core/system/status` (fallback on older versions) |
 | `get_interfaces` | ✅ | `GET /api/interfaces/overview/export` |
-| `get_interfaces_ip` | ✅ | `GET /api/interfaces/addresses/export` |
+| `get_interfaces_ip` | ✅ | `GET /api/interfaces/overview/export`; a CARP address only on the node that is MASTER for it |
 | `get_interfaces_counters` | ✅ | `GET /api/diagnostics/interface/get_interface_statistics` |
 | `get_arp_table` | ✅ | `GET /api/diagnostics/interface/get_arp` |
 | `get_ipv6_neighbors_table` | ✅ | `GET /api/diagnostics/interface/get_ndp` |