fix: pass observer name (msg.origin) to packet insert and observer upsert

Lincomatic MQTT packets include origin field with friendly name but
we were only using it in status handler. Now both packet and observer
records get the name.

server.js

@@ -472,6 +472,7 @@ for (const source of mqttSources) {
           raw_hex: msg.raw,
           timestamp: now,
           observer_id: observerId,
+          observer_name: msg.origin || null,
           snr: msg.SNR ?? null,
           rssi: msg.RSSI ?? null,
           hash: computeContentHash(msg.raw),
@@ -505,7 +506,7 @@ for (const source of mqttSources) {
         }
 
         if (observerId) {
-          db.upsertObserver({ id: observerId, iata: region });
+          db.upsertObserver({ id: observerId, name: msg.origin || null, iata: region });
         }