Hide framework plumbing in the trace view by default

A chat transaction is 212 spans, and almost all of them are Express
middleware, mongoose and mongodb calls, kong.dns lookups and raw SQL.
The flow — LibreChat to the gateway to the backend — is buried in it.

Set a default span filter on the panel: spanNameOperator "!~" against
those names with matchesOnly, so the view opens on the spans that
describe the exchange. "Show all spans" and clearing the filter both
bring them back.

Deliberately a display filter, not a source change. The spans are still
produced and still stored; only this panel's default view is quieter.
It is also the only lever that covers the LibreChat ones: LibreChat does
not use auto-instrumentations-node — it registers express, mongodb and
mongoose individually in its own code — so no environment variable
disables them, and they are the bulk of the 212.

The option names were checked against Grafana's own traces panel bundle
rather than assumed: spanName, spanNameOperator, serviceName,
serviceNameOperator, matchesOnly and criticalPathOnly all exist there,
and "!~" is among the operators it offers.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

k8s/grafana/dashboards/obs-distributed-traces.json

@@ -170,7 +170,7 @@
     {
       "type": "traces",
       "title": "Trace $traceId",
-      "description": "Grafana's own trace view: the full waterfall, every span nested in order, across LibreChat, Keycloak, the Kong gateways and the backend — no split between HTTP hops and plugins, they are one tree.\n\nClick a span to expand its attributes: method, route, status, durations, and whatever the instrumentation attached. From a span, 'Logs for this span' jumps to Loki.",
+      "description": "Grafana's own trace view: every span nested in order across LibreChat, Keycloak, the Kong gateways and the backend. Click a span to expand its attributes; from a span, 'Logs for this span' jumps to Loki.\n\nA default span filter hides the framework plumbing — Express middleware, mongoose/mongodb calls, kong.dns, raw SQL — which is most of a 212-span trace and none of the flow. Clear the filter in the panel, or toggle 'Show all spans', to get them back.\n\nThis is a DISPLAY filter: those spans are still produced and still stored in Tempo.",
       "datasource": {
         "type": "tempo",
         "uid": "tempo"
@@ -192,7 +192,26 @@
           "query": "$traceId",
           "limit": 300
         }
-      ]
+      ],
+      "options": {
+        "spanFilters": {
+          "spanName": "middleware - .*|mongoose\\..*|mongodb\\..*|kong\\.dns|SELECT|INSERT|UPDATE|DELETE|router - .*",
+          "spanNameOperator": "!~",
+          "serviceName": "",
+          "serviceNameOperator": "=",
+          "from": "",
+          "to": "",
+          "tags": [
+            {
+              "id": "1",
+              "operator": "="
+            }
+          ],
+          "matchesOnly": true,
+          "criticalPathOnly": false,
+          "query": ""
+        }
+      }
     },
     {
       "type": "row",