Add Grafana; expose VictoriaMetrics' own vmui UI

Grafana: real dashboards over VictoriaMetrics. Provisioned rather than
clicked through: a VictoriaMetrics datasource (type: prometheus — VM
speaks that query API, which is the whole point of it existing) is
baked into the chart's own datasource-provisioning config, so a fresh
install has it working with no manual setup. Admin credentials from
Vault via ExternalSecret (secretstores/grafana-admin-credentials.yaml
in devops-infra-argo-config), same pattern as every other admin
credential in this project — never plaintext in this repo. 1Gi
local-path PVC for dashboards/Grafana's own state (VictoriaMetrics
holds the actual metric data, not this). Dual LAN+Tailscale Ingress
hosts, same convention as everything externally reachable here.

Found and fixed while vendoring: helm-templates/grafana already held a
fully-vendored old Grafana chart (v6.58.7, appVersion 10.0.3) from the
original Meesho monorepo import (commit b8575bb) — generic production
config (fullnameOverride: grafana-infra-prd, GKE-shaped RBAC/PSP
defaults) unrelated to this homelab, same class of leftover as
victoria-metrics-single's collision two commits ago. Removed and
re-vendored fresh (10.5.15) as a thin wrapper, matching every other
official-chart component in this repo now.

vmui: VictoriaMetrics' own built-in UI (ad-hoc PromQL + graphs, no
saved dashboards — what Grafana is for) is served on the same
pod/port, so exposing it cost one ingress block on the
victoria-metrics-single values already committed. No new component,
no new RAM.

Verified with `helm template` against the real charts for both
components individually (Grafana: admin env vars correctly reference
the ExternalSecret's keys, datasource ConfigMap renders the intended
VictoriaMetrics URL, PVC/resources/ingress hosts all match; vmui:
ingress renders both hostnames pointing at the existing Service's named
http port) and again for the whole generic-argo-apps-chart appSpec
list — 12 Applications render, including grafana.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wajog7nELA3i8JWTjxYGHF

helm-templates/grafana/Chart.yaml

@@ -1,33 +1,20 @@
 apiVersion: v2
 name: grafana
-version: 6.58.7
-appVersion: 10.0.3
-kubeVersion: "^1.8.0-0"
-description: The leading tool for querying and visualizing time series and metrics.
-home: https://grafana.net
-icon: https://raw.githubusercontent.com/grafana/grafana/master/public/img/logo_transparent_400x.png
-sources:
-  - https://github.com/grafana/grafana
-  - https://github.com/grafana/helm-charts
-annotations:
-  "artifacthub.io/license": AGPL-3.0-only
-  "artifacthub.io/links": |
-    - name: Chart Source
-      url: https://github.com/grafana/helm-charts
-    - name: Upstream Project
-      url: https://github.com/grafana/grafana
-maintainers:
-  - name: zanhsieh
-    email: zanhsieh@gmail.com
-  - name: rtluckie
-    email: rluckie@cisco.com
-  - name: maorfr
-    email: maor.friedman@redhat.com
-  - name: Xtigyro
-    email: miroslav.hadzhiev@gmail.com
-  - name: torstenwalter
-    email: mail@torstenwalter.de
-type: application
-keywords:
-  - monitoring
-  - metric
+version: 1.0.0
+dependencies:
+  - name: grafana
+    # Pinned to the latest stable at the time this was vendored (2026-09).
+    # Bump deliberately later, with a changelog read first, same as any
+    # other chart bump in this repo.
+    #
+    # This directory already held a fully-vendored copy of an old Grafana
+    # chart (v6.58.7, appVersion 10.0.3) from the original Meesho monorepo
+    # import (commit b8575bb) — generic production config
+    # (fullnameOverride: grafana-infra-prd, GKE-shaped RBAC/PSP defaults),
+    # not anything built for this homelab. Removed and re-vendored fresh
+    # as a thin wrapper, matching the pattern every other official-chart
+    # component in this repo now uses (vault, victoria-metrics-single,
+    # vmagent, node-exporter) — a Chart.yaml dependency plus a committed
+    # .tgz, no local templates to silently drift from upstream.
+    version: 10.5.15
+    repository: https://grafana.github.io/helm-charts