ragleap-observability v0.7.0

Optional Grafana Alloy log shipper, off by default; Promtail stays the default. Verified on one kind node: a marker stream stayed in order without gaps or repeats across a switch to Alloy and back. Alloy runs as root and keeps read positions on a host path. See CHANGELOG for limits. (The merged PR title still says “wip”; the release content is final.)