Build with Podman and deploy as a rootless Quadlet on emily

- Makefile: podman build/push from the committed tree (git archive HEAD),
  tagged :<commit> + :latest; PLATFORM defaults to linux/arm64 for emily.
- deploy.sh: push the commit first, refuse a dirty tracked tree or
  HEAD != origin/main, then build and deploy that exact commit via
  -e image_tag (rollback = an older commit).
- ansible: target emily with no become. The register role writes hops.network
  (NetworkName=hops_net) plus the caddy.container.d drop-in; the hops role
  installs ~/podman-data/hops and hops.container under systemctl --user with a
  podman healthcheck gate; the caddy role appends the site blocks to the shared
  Caddyfile and reloads.
- Drop the Docker-era network role, community.docker requirements,
  ansible/files templates and docker-compose.yml.
- .containerignore replaces .dockerignore.
- README: Podman build, rootless Quadlet deploy on emily.

ansible/roles/caddy/handlers/main.yaml

@@ -1,5 +1,31 @@
 ---
+# Caddy is its own playbook (caddy/playbook.yml in the ansible-playbooks repo)
+# and a rootless Quadlet unit there. These handlers run as the connection user,
+# so `systemctl --user` and `podman exec` work without any XDG_RUNTIME_DIR
+# juggling.
+
+# Notified by roles/caddy when the Caddyfile changes. A reload keeps existing
+# connections; a restart would briefly drop every hosted site.
+#
+# Note the config path: /etc/caddy/Caddyfile is the mount inside the container,
+# not {{ caddyfile_path }}, which is the host side of it.
 - name: Reload Caddy configuration
-  ansible.builtin.command: "docker exec -w /etc/caddy {{ caddy_container }} caddy reload"
-  listen: "Reload Caddy"
+  ansible.builtin.command: >-
+    podman exec {{ caddy_name }} caddy reload --config /etc/caddy/Caddyfile
   changed_when: true
+  listen: "Reload Caddy"
+
+# Notified by roles/register when this service's network unit, or the drop-in
+# that attaches Caddy to it, is written. Quadlet has no live equivalent of
+# `docker network connect`, so the container has to be recreated — a brief
+# restart of every hosted site, not just this one.
+#
+# Defined after the reload above so that when both are notified the cheap config
+# reload happens first.
+- name: Restart Caddy
+  ansible.builtin.systemd_service:
+    name: "{{ caddy_name }}.service"
+    scope: user
+    state: restarted
+    daemon_reload: true
+  listen: Restart Caddy