Kubero template: bump pinned image from 0.9.27 to current release

[yusuf-gundogdu]

The Kubero service template (kubero-dev/kubero#754, tracked in #173) pins
tag: 0.9.27 in services/libredb-studio/app.yaml. Current release is
0.9.59 — the template is 32 releases behind.

Users deploying from the Kubero catalog get a stale build. Needs a version-bump
PR against kubero-dev/kubero, same
pattern as the original submission.

[yusuf-gundogdu]

Bump PR opened: kubero-dev/kubero#758.

Two lines in services/libredb-studio/app.yaml:

• image tag 0.9.27 to 0.9.59
• kubero.dev/template.architecture was "[]"; it now declares ["amd64", "arm64"]. The image manifest carries both, so ARM users were being filtered out of the catalog for no reason.

Verified before submitting by running the template's own defaults (image, env vars, volume mount, container port straight out of app.yaml) on 0.9.59: health endpoint green, login works with the default admin credentials, and a saved connection survives a restart. The run was on aarch64, which doubles as evidence for the arm64 claim. yamllint -c services/.yamllint reports nothing new; the single line-length warning predates this change.

Note for contrast with #222: Kubero's default JWT_SECRET is 40 characters, so the Cosmos login problem does not exist here.