fix(telemetry): set service_instance_id in [insight] so dashboards filter

beast::insight metrics exported via OTLP carried no exported_instance
label because [insight] omitted service_instance_id (only [telemetry]
set it). Every system-* dashboard filters insight metrics with
exported_instance=~"$node", and the $node template variable is sourced
from label_values(..., exported_instance) — so with the label absent,
$node was empty and all insight-backed panels showed no data.

Add service_instance_id to [insight] in both telemetry configs, matching
the [telemetry] value (xrpld-mainnet / xrpld-devnet). CollectorManager
already reads this key and passes it to OTelCollector, which sets the
service.instance.id resource attribute.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/telemetry/xrpld-telemetry-mainnet.cfg

@@ -111,6 +111,11 @@ docker/telemetry/data
 server=otel
 endpoint=http://localhost:4318/v1/metrics
 prefix=xrpld
+# Sets the OTel service.instance.id resource attribute, which Prometheus
+# exposes as the `exported_instance` label. Dashboards filter on it via the
+# $node template variable, so without this every insight-backed panel is
+# empty. Matches [telemetry] service_instance_id for a single node identity.
+service_instance_id=xrpld-mainnet
 
 # --- OpenTelemetry tracing --------------------------------------------------
 

docker/telemetry/xrpld-telemetry.cfg

@@ -109,6 +109,11 @@ docker/telemetry/data
 server=otel
 endpoint=http://localhost:4318/v1/metrics
 prefix=xrpld
+# Sets the OTel service.instance.id resource attribute, which Prometheus
+# exposes as the `exported_instance` label. Dashboards filter on it via the
+# $node template variable, so without this every insight-backed panel is
+# empty. Matches [telemetry] service_instance_id for a single node identity.
+service_instance_id=xrpld-devnet
 
 # --- OpenTelemetry tracing --------------------------------------------------