Fix Kingfisher container: add bash and coreutils for CronJob shell

Nix containers don't include a shell by default. The CronJob needs
/bin/bash for the inline script that generates timestamped filenames.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

argocd/manifests/kingfisher/cronjob.yaml

@@ -18,7 +18,7 @@ spec:
           containers:
             - name: kingfisher
               image: registry.ops.eblu.me/blumeops/kingfisher:kustomized
-              command: ["/bin/sh", "-c"]
+              command: ["/bin/bash", "-c"]
               args:
                 - |
                   set -e

containers/kingfisher/default.nix

@@ -98,6 +98,8 @@ pkgs.dockerTools.buildLayeredImage {
   name = "blumeops/kingfisher";
   contents = [
     kingfisher
+    pkgs.bashInteractive
+    pkgs.coreutils
     pkgs.cacert
     pkgs.git
     pkgs.tzdata