Follow-up pairing with the CNPG VMPodScrape (#242). Imports the
CloudNativePG dashboard (grafana.com 20417) as a GrafanaDashboard with
datasources resolved to the in-cluster VictoriaMetrics.
## Why
Deploys Grafana in-cluster (observability project) via the grafana-operator, mirroring the puppet Grafana but modernised — **CNPG** for state, **Authentik OIDC** for auth — and ports the live datasource + dashboards in as CRs.
Depends on: grafana-operator (#235, merged), grafana schemas (#236, merged), Authentik OIDC (terraform-authentik #2), Vault seeds (done), and `^grafana/` image proxy (terraform-artifactapi #5).
## Changes (`apps/base/grafana`)
- **CNPG** postgres Cluster + rw Pooler (db `grafana`); **VaultAuth** + **VaultStaticSecrets** pulling `postgres`/`oauth` credentials from `kv/kubernetes/namespace/grafana/default/*`.
- **Grafana CR**: postgres backend via the pooler; Authentik `generic_oauth` (client id/secret from the Vault-synced secret, openid/email/profile scopes, group→role mapping); `root_url` grafana.k8s.syd1.au.unkin.net.
- **1 GrafanaDatasource** — k8s VictoriaMetrics via the operator `vmselect-main` service; reuses the previous default datasource uid so the imported dashboards resolve unedited.
- **13 GrafanaDashboards** (gzipJson) exported from the current grafana.
- **Gateway API** (traefik-internal) + HTTPRoute for grafana.k8s.syd1.au.unkin.net.
- Registered in the observability ApplicationSet + project.
## Review notes
- OAuth `role_attribute_path` maps Authentik group `grafana-admins` → Admin, else Viewer — **confirm the group name**.
- `database.ssl_mode: require` against the CNPG pooler — adjust if the pooler isn't serving TLS.
- The `VictoriaLogs - cluster` dashboard has no in-cluster logs datasource yet (no VictoriaLogs in k8s) — included for completeness, will be empty until one exists.
- `make kubeconform` clean (24 resources, validated against the strict grafana schemas).
Reviewed-on: #238
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>
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