Fix fresh-deploy blockers and clean up architecture

- Seed postfix-accounts.cf before mailserver start to satisfy Dovecot's
  requirement for at least one account on first boot
- Add failed_when: false to mail user/alias list tasks (files don't exist
  on first run)
- Add forgejo_runner_version (was undefined); default to 12
- Create /srv/forgejo/data/gitea/conf before deploying app.ini
- Decouple goaccess sync from restic: new enable_goaccess_sync flag with
  its own goaccess_sync_* variables
- Move Docker installation to bootstrap exclusively; rename docker.yml to
  networks.yml (runs docker_network role only)
- Add radicale_password to vault template and setup.sh
- Fix goaccess sync tasks gated on enable_goaccess_sync
- Add upstream bug comment to authorized_key deprecation warning
- Update CLAUDE.md and README.md throughout

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

playbooks/site.yml

@@ -9,8 +9,8 @@
 - import_playbook: bootstrap.yml
   tags: [bootstrap, never]  # only runs when explicitly tagged
 
-- import_playbook: docker.yml
-  tags: [docker]
+- import_playbook: networks.yml
+  tags: [networks]
 
 - import_playbook: nebula.yml
   tags: [nebula]