Model the build on mozimo and target emily

- Makefile: PLATFORMS, tags :<commit> and :main, build-check with --pull.
- deploy.sh: push, guards, git pull --ff-only, optional --prune, image_tag.
- Replace .containerignore with .dockerignore.
- Add the opt-in image prune to the hops role.
- Tag the Caddyfile task so --skip-tags caddy works before DNS cutover.
- Trim comments and rewrite build and deploy text in plain prose.

ansible/playbook.yml

@@ -1,18 +1,7 @@
 ---
-# Hops n Grains — rootless Podman + Quadlet, behind the fleet's shared Caddy
-# unit (caddy/playbook.yml in the ansible-playbooks repo).
-#
-# Connects as the container user and runs everything as that user: the Quadlet
-# units belong to it, so the connection's PAM session is what makes
-# `systemctl --user` and `podman exec` work without any environment juggling.
-# There is deliberately no `become`: root-only prerequisites (Podman,
-# `loginctl enable-linger`, the low-port sysctl Caddy needs) belong to
-# caddy/playbook.yml, which must have run on this host first.
-#
-# gather_facts is required: podman_user, podman_data_dir and quadlet_dir are
-# derived from the user_id / user_dir facts.
-#
-# Run with: ansible-playbook -u tanshu playbook.yml
+# Hops n Grains as a rootless Podman Quadlet on emily, behind the shared Caddy.
+# Run: ansible-playbook playbook.yml -e image_tag=<commit>
+# Use --skip-tags caddy until DNS for hopsngrains.com points at emily.
 - name: Deploy Hops n Grains as a rootless Podman Quadlet
   hosts: emily
   gather_facts: true
@@ -20,17 +9,12 @@
     - vars/default.yml
 
   pre_tasks:
-    # This must happen before the app unit is started, not after: the generated
-    # hops.container 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 drop-in that attaches the shared Caddy unit to this network,
-    # which is what makes `hops` resolvable to Caddy.
-    - name: Register Hops n Grains' network with Caddy
+    # Quadlet fails unit generation when hops.network is missing, so write the
+    # network and the Caddy drop-in before the app unit starts.
+    - name: Register the Hops n Grains network with Caddy
       ansible.builtin.include_tasks: "{{ playbook_dir }}/roles/register/tasks/main.yaml"
 
   roles:
-    # The app: data directory, .env, the Quadlet unit, start + healthcheck.
     - hops
-    # Appends this site's blocks to the shared Caddyfile and reloads Caddy.
+    # The Caddyfile task is tagged caddy. Skip it until DNS points here.
     - caddy