chore: update CozyStack upstream to v1.6.1

[kingdonb]

🤖 Automated CozyStack Dependency Update

This PR updates our CozyStack upstream release pin.

Changes:

• Release: v1.6.1
• Released: 2026-08-05T10:00:09Z
• Patch compatibility: failure

Changes in v1.6.1 (since v1.6.0)

8f4c19da chore(release): promote v1.6.1-rc.1 -> v1.6.1 (#3550)
8a43376e chore(release): remove accidental tooling gitlink
781328eb docs: add changelog for v1.6.1
1a882bbf Prepare release v1.6.1 (promoted from v1.6.1-rc.1)
70d0c15b Prepare release v1.6.1-rc.1
76062f58 [Backport release-1.6] fix(postgres-operator): align CNPG operator and CRDs to 1.28.2 for PVC resize-deadlock fix (#3542)
2258d2c6 fix(postgres-operator): align CNPG operator and CRDs to 1.28.2 for PVC resize-deadlock fix
3ba087d6 [Backport release-1.6] chore(etcd-operator): bump etcd-operator to v0.5.4 (#3538)
3a7df639 test(etcd-operator): pin deployment unittest to v0.5.4
ab1ec698 chore(etcd-operator): bump etcd-operator to v0.5.4
de8483cf [Backport release-1.6] fix(kubernetes): render the talos-reconcile Job for the default md0 group (#3536)
8c4947ba fix(kubernetes): render the talos-reconcile Job for the default md0 group
6a5ea552 ci(release): carry the finalize fixes onto the 1.6 line (#3530)
6fe15b0b ci(release): carry the finalize fixes onto the 1.6 line
09067861 [Backport release-1.6] fix(keycloak-configure): patch HelmRelease in release namespace on teardown (#3478)
3b96ef3c chore(release): don't activate kubernetes-nodes on the release-1.6 line (#3437)
042c69cb chore(release): don't activate kubernetes-nodes on the release-1.6 line
8d9beb4e [Backport release-1.6] fix(ci): overlay images from the PR base branch, and publish per-line artifacts (#3514)
e226b85f fix(ci): overlay images from the PR base branch, and publish per-line artifacts
09f4cd10 fix(ci): only overlay current-main images on main-based PRs

🧪 Pre-flight Checks

• Latest non-prerelease release tag identified
• Patch compatibility tested
  - [ ] ⚠️ Patch conflicts detected - manual review required

🚀 Next Steps

1. Review the upstream changes above
2. Verify CI pipeline passes with new upstream
3. Test ARM64 build with new CozyStack version
4. Merge when ready

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This PR was automatically created by the dependency update workflow