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/playbook.yml

@@ -1,23 +1,5 @@
 ---
-# Nextcloud as a rootless Podman Quadlet unit, behind the shared Caddy, with its
-# database in the shared Postgres and its cache in the shared Valkey. Each of
-# those is its own playbook and has to have been run first: caddy, postgres,
-# valkey, then this.
-#
-# Idempotent and standalone: the first run creates and starts the container (a
-# fresh webroot then serves the setup wizard), and later runs converge it —
-# Quadlet recreates the container when the unit or its environment changes.
-#
-# Runs as the connection user with no become: the units belong to that user, so
-# the SSH session's own PAM session is what makes `systemctl --user` work.
-# gather_facts is required — podman_user and the home directory come from the
-# user_id / user_dir facts.
-#
-# The rootless-Podman prerequisites (podman, lingering, the low-port sysctl, the
-# Quadlet directory) are not applied here; they are the shared task file at
-# caddy/roles/podman, and a host that has run caddy/playbook.yml has them.
-#
-# Run with: ansible-playbook -u tanshu nextcloud/playbook.yml
+# Requires caddy, postgres, and valkey to have run first.
 - name: Deploy Nextcloud as a rootless Podman Quadlet
   hosts: emily
   gather_facts: true
@@ -25,29 +7,12 @@
     - vars/default.yml
 
   pre_tasks:
-    # This must happen before the app unit is started, not after: the generated
-    # unit references {{ network_name }}.network, and Quadlet fails *unit
-    # generation* (so `systemctl --user start` reports "unit not found") when a
-    # referenced .network file does not exist yet. The same include writes the
-    # Caddy-side drop-in that attaches Caddy to this network, and both attaches
-    # below need the network unit to exist as well.
-    #
-    # network_name is a play var, so the include can see it directly.
+    # Quadlet needs the network unit before it generates the app unit.
     - name: Register Nextcloud's network with Caddy
       ansible.builtin.include_tasks: "{{ playbook_dir }}/../caddy/roles/register/tasks/main.yaml"
 
   roles:
-    # Attaches this app's network to the shared Postgres unit, which is what
-    # makes config.php's `db` host resolve, and owns the "Restart Postgres"
-    # handler that postgres/roles/attach notifies. Runs first so the database is
-    # reachable before the app starts.
     - postgres
-    # The same at the cache end: attaches this app's network to the shared Valkey
-    # unit, which is what makes config.php's `redis` host resolve, and owns the
-    # "Restart Valkey" handler that valkey/roles/attach notifies.
     - valkey
-    # The app: the webroot, the 0600 environment file, the Quadlet unit, the
-    # background-job timer, start + verify.
     - nextcloud
-    # Appends this site's block to the shared Caddyfile and reloads Caddy.
     - caddy