feat: add Hetzner-hosted todo application stack

Implement the server-rendered Go todo application with PostgreSQL persistence, Tailwind styling, health checks, and test coverage.

Provision production and staging infrastructure with OpenTofu, including private networking, static IPs, Object Storage backups, and load balancing.

Configure Rocky Linux hosts with Ansible, rootless Podman, PostgreSQL, WAL-G backup automation, staging restores, and generated inventory.

ansible/roles/postgres/templates/pg_hba.conf.j2

@@ -0,0 +1,4 @@
+local   all             postgres                                peer
+local   all             all                                     peer
+host    {{ app_db_name }} {{ app_db_user }} 127.0.0.1/32         scram-sha-256
+host    all             all           ::1/128                    scram-sha-256

ansible/roles/postgres/templates/postgresql.conf.j2

@@ -0,0 +1,20 @@
+data_directory = '{{ postgres_data_dir }}'
+listen_addresses = '127.0.0.1'
+port = 5432
+max_connections = 100
+shared_buffers = 256MB
+password_encryption = 'scram-sha-256'
+wal_level = replica
+max_wal_senders = 5
+wal_compression = on
+{% if deployment_environment == 'prod' %}
+archive_mode = on
+archive_command = '/usr/local/sbin/wal-g-postgres wal-push %p'
+archive_timeout = 300
+{% else %}
+archive_mode = off
+archive_command = ''
+{% endif %}
+logging_collector = on
+log_directory = 'log'
+log_filename = 'postgresql-%a.log'