feat(valkey): one Valkey instance per application (1.0.0+up9.1.2.alpine)

A new chart for a single Valkey instance per application, replacing the
shared cluster-redis whose separation rests on one ACL file in one
1Password field - a construction in which every change touches six
applications and which cost a month of Paperless standstill.

Shape: StatefulSet with one replica, ClusterIP Service, no cluster mode,
no Ingress and no value to add one.

The password arrives as a finished configuration line ("requirepass
<secret>") in the 1Password field auth-conf, is mounted as a file and
included by the main configuration - never in argv, never in the
environment. The include is rendered last, so nothing in extraConfig can
override it. Because a misspelled or empty field would leave an open
server that looks perfectly healthy, an init container greps the mounted
file for the line and refuses to start the pod without it; it never
prints the file.

maxmemory is derived from the computed memory limit (maxmemoryFactor,
default 0.75) and a configured value above that limit aborts the render:
otherwise the kubelet's OOM kill decides what the eviction policy was
configured to decide. Persistence and eviction are documented as pairs -
queue (PVC + noeviction, the default) and cache (emptyDir +
allkeys-lru) - and the combination "no persistence + noeviction" carries
a warning in values.yaml and in NOTES.txt.

Probes: valkey-cli ping as an exec probe, authenticated through
VALKEYCLI_AUTH read out of the mounted file, with "-e" and an assertion
on the answer PONG. Without -e valkey-cli exits 0 on an error reply
(valkey 9.1.2, src/valkey-cli.c: the config.set_errcode branch in
cliReadReply), which would make the probe unable to fail.

Hardening: uid 999 / gid 1000 - the image's own valkey user - with
fsGroup matching, runAsNonRoot, readOnlyRootFilesystem, all capabilities
dropped and seccompProfile RuntimeDefault in the pod context so the init
container is covered too. /data is the only writable path.

NetworkPolicy on by default (first chart in this repo with one), with a
switch and a list of additional namespaces; values.yaml names that it is
only a boundary where the CNI enforces policies.

Wiring: publish-valkey.yml, the chart-name choice list, ci/valkey
fixtures for the persistent variant, a plain docker-versioning Renovate
block, README chart row.

.github/workflows/change-app-version.yml

@@ -39,6 +39,7 @@ on:
           - bentopdf
           - ytdlp-web-player
           - sure
+          - valkey
           # freesailarr is deliberately absent: none of its ten images takes
           # its tag from appVersion (they are all pinned in its values.yaml),
           # so this workflow would rewrite appVersion and republish the chart

.github/workflows/publish-valkey.yml

@@ -0,0 +1,15 @@
+name: Publish Valkey Helm Chart
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+    paths:
+      - valkey/**
+jobs:
+  publish-valkey:
+    name: Publish Valkey Helm Chart
+    uses: ./.github/workflows/publish-helm-chart.yml
+    with:
+      chart-name: 'valkey'
+    secrets: inherit