agent-platform release v4.9.4

A connectivity release no longer restarts the portal (giantswarm/agent-platform#424): the Backstage config-reload hook hashed the whole rendered app-config ConfigMap, metadata included, and labels.common carries helm.sh/chart: agent-platform-connectivity-<version> — the connectivity chart is versioned with the meta chart, so the checksum it stamped into the Backstage Deployment moved on every release and rolled the pod (~60 s until Ready; the terminated pod’s in-flight streams to kagent surfaced as The kagent API is not available / “Could not load this session”) with no app-config change behind it (4.9.1 and 4.9.2 on the first 4.x installation, 2026-09-13). The hook now hashes the ConfigMap’s .data only — the app-config document the pod mounts — so the checksum is stable across releases and still moves on a real change (identity block, installation name, agentPlatform.*, hostnames); the render fails loudly if the app-config renders without data. make verify-wiring asserts both: two renders differing only in .Chart.Version yield the same checksum, and each of an installation-name, tenant-identity and issuer change yields a different one. Installations act: none — the release rolls through the connectivity range; the first release carrying it rolls the portal one last time (the checksum’s shape changes), every one after it leaves the pod alone.