Cut the comment bloat from the Podman playbooks

Comment blocks now stay within three lines and explain only the non-obvious. Long histories, include examples, and commented-out code are gone. No task, key, or value changed; the only data change is comment text inside the generated unit files.

nextcloud/roles/postgres/tasks/main.yaml

@@ -1,21 +1,12 @@
 ---
-# Attach this app's network to the shared Postgres unit, and make sure the
-# database exists.
-
 - name: Attach Nextcloud to Postgres
   ansible.builtin.include_tasks: "{{ playbook_dir }}/../postgres/roles/attach/tasks/main.yaml"
 
-# The restart that joins Postgres to nextcloud_net is a handler, so by default it
-# would run at the end of the play — after the app has started and failed to
-# resolve `db`. Flushing first also applies the Caddy restart queued by the
-# register pre_task. Nothing is pending on later runs.
+# The restart that joins Postgres to nextcloud_net is a handler, so flush it before the app starts. This also applies the queued Caddy restart.
 - name: Apply the network change before starting Nextcloud
   ansible.builtin.meta: flush_handlers
 
-# Postgres ships one default database and only this app knows the name of its own,
-# so on a fresh cluster the installer would otherwise fail with "database
-# nextcloud does not exist". The retry is for the restart the flush above may have
-# just done.
+# On a fresh cluster the installer would fail without this database, and the retry covers the restart the flush did.
 - name: Check whether the {{ pg_database }} database exists
   ansible.builtin.command: >-
     podman exec -e PGPASSWORD={{ pg_password }} {{ postgres_container }}