feat(semaphore): rewrite role with rootful Podman Quadlet + PostgreSQL

Complete rewrite of the semaphore role. Supersedes three prior
iterations whose admin-user-creation logic was unreliable across
Semaphore CLI versions.

Architecture:
  - Rootful Podman Quadlet under /etc/containers/systemd/
  - Separate PostgreSQL 16-alpine container on a user-defined
    podman network (semaphore-net)
  - Named volumes for both data stores (semaphore_data,
    semaphore_postgres_data) so container recreation is
    non-destructive
  - Pinned image tags: semaphoreui/semaphore:v2.18.5-ansible2.16.5
    and postgres:16-alpine
  - Post-deploy HTTP health check fails the playbook if Semaphore
    doesn't respond on /api/ping within ~60s

Admin user creation remains intentionally manual after first deploy;
the role README documents the exact podman exec command.

Removes the duplicate deploy_semaphore.yml and the now-unneeded
cleanup_semaphore.yml; day1_deploy_semaphore.yml is the canonical
entry point.

ansible/roles/semaphore/tasks/semaphore.yml

@@ -0,0 +1,24 @@
+---
+# ============================================================================
+# Semaphore container (Quadlet)
+# ============================================================================
+
+- name: Deploy Semaphore Quadlet
+  ansible.builtin.template:
+    src: semaphore.container.j2
+    dest: "{{ semaphore_quadlet_dir }}/{{ semaphore_container_name }}.container"
+    owner: root
+    group: root
+    mode: "0644"
+  register: semaphore_quadlet
+
+- name: Reload systemd to pick up Quadlet changes
+  ansible.builtin.systemd:
+    daemon_reload: true
+  when: semaphore_quadlet.changed
+
+- name: Ensure Semaphore container is started and enabled
+  ansible.builtin.systemd:
+    name: "{{ semaphore_container_name }}.service"
+    state: started
+    enabled: true