anubis: fix image ref typo in deploy pull, health probe exec form, unit alias tag

Three compounding deploy-handler bugs found by live deployment:
- podman image exists/pull used a mixed-case ghcr.io ref that podman's
  reference parser rejects before any network I/O (repository name must be
  lowercase); all refs now lowercase — ghcr resolves case-insensitively.
- the unit runs the image under a localhost/ alias tag: this host's podman
  5.7 quadlet path fails container create with 'image not known' for
  registry-prefixed refs even when present in storage (verified live).
- the health probe was shell-form and the distroless ko-build image has no
  shell; HealthCmd is now a JSON exec-form array, which passes through the
  quadlet generator's argv assembly verbatim.

Tests updated to assert the alias-tag reality plus the pull guard.

scripts/deploy-remote.sh

@@ -555,7 +555,7 @@ deploy_anubis() {
     # The image lives on ghcr.io; pull once, then the unit runs it from
     # local storage (Pull=never keeps boots off the registry).
     if ! podman image exists ghcr.io/techarohq/anubis:v1.13.0; then
-        podman pull ghcr.io/techaroq/anubis:v1.13.0
+        podman pull ghcr.io/techarohq/anubis:v1.13.0
     fi
     # The unit runs the localhost/ alias (see the unit file comment): this
     # host's podman quadlet path cannot resolve registry-prefixed refs from