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/handlers/main.yml

@@ -1,3 +1,4 @@
 ---
-# Handlers kept for potential future use or legacy paths.
-# Quadlet deployment now handles reload + start directly in the task block.
+# handlers intentionally minimal — Quadlet-managed containers restart
+# automatically on unit file change after `systemctl daemon-reload`, and
+# the role triggers daemon-reload + systemd state checks explicitly.