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>

config.yaml

@@ -194,7 +194,7 @@ locations:
       - names: ["showpi1"]
       - names: ["showpi2"]
         macs: ["d8:3a:dd:e3:5b:db"]
-      - names: ["AP"]
+      - names: ["EAP770"]
         macs: ["a8:29:48:ca:11:40"]
 
     - name: Sound Control