feat(state): metric-servers (InfluxDB / Graphite) as a GitOps state family — /cluster/metrics/server

[fabriziosalmi]

Why

/cluster/metrics/server (external InfluxDB / Graphite metric targets) is a small, self-contained CRUD surface — an easy promotion to a GitOps state family via the cheap epic-#74 pattern (model → export/diff/apply/preflight → Resource::all()). Declaring your metrics fan-out in git is a natural fit for a GitOps controller.

Scope

• MetricServerDecl (type influxdb/graphite, host, port, proto, ...), new --resource metric-servers token, full lifecycle + preflight.
• Preflight: a metric-server delete is low blast-radius (Notice/Warning — you lose telemetry, nothing guest-facing breaks).

Blocker

InfluxDB bearer tokens are write-only on PVE → blocked by the secret-ref / elide-on-export convention (#178). Graphite (no token) could land first; Influx targets follow #178.

Notes

• Effort: S (smallest of the promotion candidates — good first one to land right after feat(state): secret-ref / elide-on-export convention for secret-bearing state families #178).