chart+argocd: switch Image Updater to semver on git release tags

newest-build on raw short-SHA tags is non-deterministic: it sorts by
image build date, which rebuilt machine-commit images had scrambled
(picked fe4af75 over HEAD). SHA tags have no age-ordering.

Switch to semver tracking on vX.Y.Z release tags:
- imageupdater: updateStrategy semver, allowTags ^v[0-9]+\.[0-9]+\.[0-9]+$,
  helm name+tag mapping (image.repository/image.tag)
- values: pin image.tag to v0.1.0

Updates now trigger on deliberate release tags, not every main push -
correct cadence for an operator.

Author: MicheleCampi

argocd/imageupdater.yaml

@@ -16,10 +16,11 @@ spec:
         - alias: "operator"
           imageName: "ghcr.io/michelecampi/vllm-coldstart-operator"
           commonUpdateSettings:
-            updateStrategy: "newest-build"
-            allowTags: "regexp:^[0-9a-f]{7}$"
+            updateStrategy: "semver"
+            allowTags: "regexp:^v[0-9]+\\.[0-9]+\\.[0-9]+$"
             platforms:
               - "linux/amd64"
           manifestTargets:
             helm:
+              name: "image.repository"
               tag: "image.tag"

chart/values.yaml

@@ -4,7 +4,7 @@
 #    via git write-back. When spec is set, the image helper uses it verbatim.
 image:
   repository: ghcr.io/michelecampi/vllm-coldstart-operator
-  tag: af7d696
+  tag: v0.1.0
   pullPolicy: IfNotPresent
   # -- Managed by ArgoCD Image Updater. Full image reference, takes precedence.
   spec: ghcr.io/michelecampi/vllm-coldstart-operator:latest@sha256:d7ccf8580f42a87ea401f13eed9188fc8892b07bd2212357e87c7919f71fb98d