chore(flux): migrate image-automation API v1beta2 -> v1

Migrate image.toolkit.fluxcd.io/v1beta2 -> /v1 for ImageRepository,
ImagePolicy, and ImageUpdateAutomation ahead of the Flux v2.7+ upgrade
(cluster-upgrade-plan §3.2). Flux v2.4 (current) already serves /v1, so
migrating the manifests now is a safe no-op at runtime.

- catalog/render.py: r_image_automation emits v1 for ImageRepository/ImagePolicy
- platform/image-automation/{image-update-automation,per-service/pihole.example}
- conformance L3 hands-off-update chainsaw applies v1 CRs
- conformance L1 goldens re-rendered to match (apiVersion-only diff)

No spec-field changes required: all spec fields used (image, interval,
imageRepositoryRef, filterTags.pattern/extract, policy.semver.range,
sourceRef, git.*, update.strategy/path) are unchanged in v1; the v1
messageTemplate already uses .Changed (not the removed .Updated).
apps/ golden unaffected (canonical render uses --no-image-automation).

Co-Authored-By: Claude Opus 4.8 <[email protected]>

catalog/render.py

@@ -667,7 +667,7 @@ def r_image_automation(s: dict) -> list:
     upd = s["update"]
     interval = "1h0m0s"
     imagerepo = {
-        "apiVersion": "image.toolkit.fluxcd.io/v1beta2",
+        "apiVersion": "image.toolkit.fluxcd.io/v1",
         "kind": "ImageRepository",
         "metadata": {"name": s["name"], "namespace": s["name"]},
         "spec": {"image": image, "interval": interval},
@@ -682,7 +682,7 @@ def r_image_automation(s: dict) -> list:
     else:
         policy_spec["policy"] = {"semver": {"range": ">=0.0.0"}}
     imagepolicy = {
-        "apiVersion": "image.toolkit.fluxcd.io/v1beta2",
+        "apiVersion": "image.toolkit.fluxcd.io/v1",
         "kind": "ImagePolicy",
         "metadata": {
             "name": s["name"],