fix: use public DNS on phone-hotspot (carrier resolver fails .dev tunnel)

- yaris_uplink configure() keyfile: dns=8.8.8.8;1.1.1.1 + ignore-auto-dns=true
  so the Pi doesn't rely on the phone's DHCP DNS, which failed to resolve
  yaris.ceaf.dev (NameResolutionError) and broke uploads on the hotspot
- test asserts the DNS lines are written to the keyfile

deploy/yaris_uplink.py

@@ -379,6 +379,11 @@ method=auto
 dhcp-send-hostname=true
 dhcp-hostname=yaris
 dhcp-client-id=yaris-obd
+# Use public DNS instead of the phone's DHCP-provided resolver — some
+# carrier/hotspot resolvers fail to resolve the server hostname (e.g. the
+# .dev Cloudflare tunnel), which broke uploads on the phone hotspot.
+dns=8.8.8.8;1.1.1.1;
+ignore-auto-dns=true
 
 [ipv6]
 method=auto