renovate: chart-aware config with an automatic version bump

Renovate only ever rewrites appVersion or an image tag, so every PR it
opened against a chart directory failed the build-chart version check
(#138, #139). ci/renovate-bump-chart.sh recomputes
version: <semver>+up<appVersion> as a postUpgradeTasks hook: chart major
when the app major moves, chart patch otherwise.

Each chart renders its main image as <repo>:{{ .Chart.AppVersion }}, so
repository and version live in different files and Renovate cannot join
them. The mapping is one customManager per chart in renovate.json5,
deliberately not a comment inside each Chart.yaml - that would touch all
20 chart directories and force 20 publishes for a comment change.

Patch and digest updates automerge after a 3-day minimumReleaseAge once
the pipeline is green; majors arrive one line at a time to match the
stepwise app-major procedure. ci/** stays excluded: the install-test
fixtures pin throwaway infrastructure to major lines on purpose.

CLAUDE.md

@@ -40,6 +40,7 @@ Copy `template-chart/` and replace every `xxx` placeholder — in file names (`t
 1. Add `.github/workflows/publish-<chart-name>.yml` (copy an existing one, e.g. `publish-outline.yml`) — it triggers on pushes to `main` touching `<chart-name>/**` and calls the reusable `publish-helm-chart.yml`.
 2. Add the chart name to the `chart-name` choice list in `.github/workflows/change-app-version.yml`.
 3. Add install-test fixtures under `ci/<chart-name>/` (`test-values.yaml`, `fixtures.yaml`) or an entry with justification in `ci/excluded-charts.txt` — the PR install-test fails if both are missing.
+4. Add a `customManagers` block for the chart's main image in `renovate.json5` (one per chart, since the image repository lives in the template and the version in `Chart.yaml`) — without it Renovate never updates that chart's app version. See README section "Dependency updates (Renovate)".
 
 ## Versioning scheme