searxng: new chart (1.0.0+up2026.8.22.9fea41204)

SearXNG as a stateless Deployment plus a settings ConfigMap, with the four CI
steps a new chart needs: publish workflow, change-app-version choice list,
ci/searxng/ fixtures and a renovate.json5 block.

Three points where the chart is not a cyberchef with another name:

* The image entrypoint writes settings.yml into /etc/searxng only when the
  file is missing. The chart always mounts one by subPath, so the copy and
  the random-secret sed never run and the container needs no write access
  there - which is what allows readOnlyRootFilesystem: true.
* The signing key is a required OnePasswordItem, not a ConfigMap key. It
  signs the settings cookie and the image-proxy URLs, and the entrypoint's
  self-generating fallback cannot fire here, so without it the instance would
  run on the literal "ultrasecretkey" - which webapp.py refuses with exit 1.
* All three probes use /healthz, the only path the bot detection lets through
  unconditionally. Measured: with the limiter active, "/" answers 429 while
  /healthz still answers 200.

ingress.domain is read a second time outside the Ingress template, for
SEARXNG_BASE_URL, and carries its own required() there - so it stays
mandatory with the Ingress switched off.

The Renovate versioning regex deviates from the plan on the issue and matches
the commit hash WITHOUT capturing it. Renovate parses a "build" group with
Number.parseInt, so a hash becomes the digits leading it; measured on
renovate 41.173.1 and 44.48.0, the planned form reports an image pushed
earlier the same day as an update to a newer one. Reasoning in the block and
in README.

searxng/templates/searxng.configmap.yaml

@@ -0,0 +1,14 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: "{{ .Release.Name }}-{{ .Chart.Name }}-configmap"
+data:
+  # Mounted at /etc/searxng/settings.yml via subPath. That path is not free
+  # choice: the image exports __SEARXNG_SETTINGS_PATH=/etc/searxng/settings.yml
+  # and its entrypoint creates the file from its own template only when it does
+  # NOT exist. Because this mount is always there, the entrypoint finds the
+  # file, skips both the copy and the sed that would otherwise invent a random
+  # secret_key, and never needs to write into /etc/searxng - which is what lets
+  # the container run with a read-only root filesystem.
+  settings.yml: |
+    {{- include "searxng.settingsYaml" . | nindent 4 }}