Run the build on Podman and deploy as a rootless Podman Quadlet

- Makefile: podman build + push instead of docker buildx. build-production
  clones the git remote and builds from it; build-check / build-check-local
  build without pushing. Single-architecture (PLATFORM-overridable) rather
  than a multi-arch manifest.
- deploy.sh: connect as the unprivileged container user; no become.
- ansible: target emily, rootless Podman Quadlet behind the fleet's shared
  Caddy unit (caddy/playbook.yml in ansible-playbooks).
  - register role writes greatbear.network (NetworkName=greatbear_net) and
    the caddy.container.d drop-in that puts Caddy on it.
  - greatbear role: podman login/pull, ~/podman-data/greatbear + .env,
    greatbear.container (UserNS=keep-id:uid=0,gid=0, EnvironmentFile,
    Network, Volume, no published ports), systemctl --user start and a
    podman healthcheck gate, with a diagnostics rescue block.
  - caddy role appends the site blocks to the shared Caddyfile and reloads;
    handlers reload vs. recreate Caddy (a new network drop-in re-creates it).
  - drop the network role, the community.docker requirements and the
    ansible/files/ templates.
- .containerignore replaces .dockerignore (Buildah reads it natively).
- README: Podman build, rootless Quadlet deploy. No data migration step —
  there is no PocketBase state to carry over.

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