Add TP-Link AP support with wireless client sub-locations

- Add NodeType enum (switch, ap, wireless_client, wired_client)
- Poll SNMPv2c and SNMPv3 in parallel to win race with ping
- Render APs with bordered sub-locations containing wireless clients
- Fall back to parent interface stats when child lacks them
- Log when unreachable nodes become reachable via merge

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tendrils.go

@@ -333,7 +333,7 @@ func (t *Tendrils) pollNode(node *Node) {
 
 	if !t.DisableSNMP {
 		for _, ip := range ips {
-			t.querySNMPDevice(node, ip)
+			t.pollSNMP(node, ip)
 		}
 	}