C1: borgmatic shower SQLite dump via ssh to ringtail

The shower dump hook referenced kubectl --context=k3s-ringtail, but
indri's kubeconfig deliberately doesn't carry the ringtail
credentials. Since PR #349 (2026-05-11), nightly borgmatic runs have
failed at the before_backup hook, aborting both sifaka-borg-backups
and borgbase-offsite.

Rewrite the dump to ssh into ringtail and run k3s kubectl there.
/etc/rancher/k3s/k3s.yaml on ringtail is mode 644, so no sudo is
needed; the ssh user (eblume) reads it directly. Dump file is
created in the pod via sqlite3.backup, copied to ringtail's host
filesystem via k3s kubectl cp, then scp'd back to indri.

Template gains a `ssh_host` field on dump entries — when set, uses
the ssh path; when absent (as for mealie), uses local kubectl with
the existing `context` field.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ansible/roles/borgmatic/tasks/main.yml

@@ -49,6 +49,20 @@
     mode: '0700'
   when: borgmatic_k8s_sqlite_dumps | length > 0
 
+- name: Ensure ~/bin exists
+  ansible.builtin.file:
+    path: "{{ ansible_env.HOME }}/bin"
+    state: directory
+    mode: '0755'
+  when: borgmatic_k8s_sqlite_dumps | length > 0
+
+- name: Deploy k8s SQLite dump helper script
+  ansible.builtin.template:
+    src: k8s-sqlite-dump.sh.j2
+    dest: "{{ ansible_env.HOME }}/bin/borgmatic-k8s-sqlite-dump"
+    mode: '0755'
+  when: borgmatic_k8s_sqlite_dumps | length > 0
+
 - name: Deploy borgmatic configuration
   ansible.builtin.template:
     src: config.yaml.j2