feat(k8s): make the OTLP trace endpoint a chart value (refs #186)

otelEndpoint defaults to the chart's own tempo; deploy overrides it from the
OTEL_ENDPOINT repo variable, so the labs cluster can ship traces to the
monitoring stack's Tempo instead of failing every export.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.gitea/workflows/deploy.yaml

@@ -34,6 +34,9 @@ jobs:
       # `true` fills in the medewerker OTP step for the public demo (chart value
       # demo.otpAutofill). The fixture secret is committed: demo only.
       OTP_AUTOFILL: ${{ vars.OTP_AUTOFILL }}
+      # Tempo for the services' traces, e.g. http://tempo.monitoring.svc:4317 (the
+      # cluster monitoring stack, Infra repo). Empty = the chart default.
+      OTEL_ENDPOINT: ${{ vars.OTEL_ENDPOINT }}
     steps:
       - uses: https://github.com/actions/checkout@v4
 
@@ -100,7 +103,7 @@ jobs:
           make k8s-reseed \
             TALOS_HOST=${TALOS_HOST:-localhost} \
             K8S_REGISTRY=${TALOS_VM_IP:-192.168.122.173}:30500 \
-            K8S_SET="${KEYCLOAK_URL:+--set keycloakUrl=$KEYCLOAK_URL} --set demo.otpAutofill=${OTP_AUTOFILL:-false}"
+            K8S_SET="${KEYCLOAK_URL:+--set keycloakUrl=$KEYCLOAK_URL} --set demo.otpAutofill=${OTP_AUTOFILL:-false}${OTEL_ENDPOINT:+ --set otelEndpoint=$OTEL_ENDPOINT}"
 
       # `dev` is a mutable tag and helm sees an unchanged pod template, so the
       # new images only land on a restart (pullPolicy is already Always).