feat: the managers', the portal's and mcp-kubernetes' traces to the platform's OTLP gateway

[QuentinBisson]

Problem

None of the managers, the portal or mcp-kubernetes exported traces, so a tool call through muster ended at muster's span. Part of giantswarm/giantswarm#36711.

Change

• model-manager, agent-manager, vm-manager, cluster-manager and backstage get observability.otel.{endpoint,protocol,headers}: auto, and mcp-kubernetes gets mcpKubernetes.instrumentation.{tracingExporter,otlpEndpoint,otlpInsecure,otlpProtocol,otlpHeaders}: auto. agent-platform.shape.otlp fills them from global.observability.traces.otlp, with the tenant as X-Scope-OrgID. mcp-kubernetes takes host:port, otlpInsecure comes from the scheme, and tracingExporter is otlp while an endpoint is set.
• Each manager's and the portal's egress policy opens the resolved endpoint, in both flavours. mcp-kubernetes' own policy already admits the cluster.
• The floors move to the first releases that export, all published: model-manager 1.3.0, agent-manager 1.2.0, vm-manager 0.24.0, cluster-manager 0.19.0, backstage 2.68.0, mcp-kubernetes 1.3.0. The BOM pins them. verify-otlp-global covers the six components.

Replaces #698, which closed when #695's branch was deleted. Every verify target passes locally, verify-components-charts in strict mode too.

Checklist

• Update changelog in CHANGELOG.md.
• Make sure values.yaml and values.schema.json are valid.

[circleci-architect]

Published Helm chart agent-platform

4.77.1-rb7aa56eet20260925133748he53385f

Chart	agent-platform
Version	4.77.1-rb7aa56eet20260925133748he53385f
OCI reference	oci://gsoci.azurecr.io/charts/giantswarm/agent-platform:4.77.1-rb7aa56eet20260925133748he53385f
Digest	sha256:23168d1e1a78d3e77257e0db2755b544837e1443331a6aba770eb2060da1ae24
Registry	public — gsoci.azurecr.io
Git catalog	giantswarm-test-catalog (index)

Pull this chart

helm pull oci://gsoci.azurecr.io/charts/giantswarm/agent-platform --version 4.77.1-rb7aa56eet20260925133748he53385f

_{Posted by architect-orb · build 14460 · commit e53385f · updated in place on every push}

[circleci-architect]

Published Helm chart agent-platform-connectivity

4.77.1-rb7aa56eet20260925133748he53385f

Chart	agent-platform-connectivity
Version	4.77.1-rb7aa56eet20260925133748he53385f
OCI reference	oci://gsoci.azurecr.io/charts/giantswarm/agent-platform-connectivity:4.77.1-rb7aa56eet20260925133748he53385f
Digest	sha256:c448d779c7e523e71a29e6e075e14bc9a83e301964974af7b44318059f6c2605
Registry	public — gsoci.azurecr.io
Git catalog	giantswarm-test-catalog (index)

Pull this chart

helm pull oci://gsoci.azurecr.io/charts/giantswarm/agent-platform-connectivity --version 4.77.1-rb7aa56eet20260925133748he53385f

_{Posted by architect-orb · build 14459 · commit e53385f · updated in place on every push}