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/tasks/main.yml

@@ -0,0 +1,75 @@
+---
+- name: Initialize PostgreSQL data directory
+  ansible.builtin.command:
+    argv: [postgresql-setup, --initdb]
+  args:
+    creates: "{{ postgres_data_dir }}/PG_VERSION"
+
+- name: Create canonical PostgreSQL configuration directory
+  ansible.builtin.file:
+    path: /etc/todo-postgresql
+    state: directory
+    owner: root
+    group: postgres
+    mode: "0750"
+
+- name: Render canonical PostgreSQL server configuration
+  ansible.builtin.template:
+    src: postgresql.conf.j2
+    dest: /etc/todo-postgresql/postgresql.conf
+    owner: root
+    group: postgres
+    mode: "0640"
+  notify: Restart PostgreSQL
+
+- name: Render canonical PostgreSQL client authentication
+  ansible.builtin.template:
+    src: pg_hba.conf.j2
+    dest: /etc/todo-postgresql/pg_hba.conf
+    owner: root
+    group: postgres
+    mode: "0640"
+  notify: Restart PostgreSQL
+
+- name: Install PostgreSQL configuration in data directory
+  ansible.builtin.copy:
+    src: "/etc/todo-postgresql/{{ item }}"
+    dest: "{{ postgres_data_dir }}/{{ item }}"
+    remote_src: true
+    owner: postgres
+    group: postgres
+    mode: "0600"
+  loop:
+    - postgresql.conf
+    - pg_hba.conf
+  notify: Restart PostgreSQL
+
+- name: Start PostgreSQL
+  ansible.builtin.systemd_service:
+    name: "{{ postgres_service }}"
+    enabled: true
+    state: started
+
+- name: Apply PostgreSQL configuration before provisioning
+  ansible.builtin.meta: flush_handlers
+
+- name: Provision application database role
+  ansible.builtin.command:
+    argv: [psql, --set, "role={{ app_db_user }}", --set, "password={{ app_db_password }}", --dbname, postgres]
+    stdin: |
+      SELECT format('CREATE ROLE %I LOGIN PASSWORD %L', :'role', :'password')
+      WHERE NOT EXISTS (SELECT FROM pg_roles WHERE rolname = :'role') \gexec
+      SELECT format('ALTER ROLE %I LOGIN PASSWORD %L', :'role', :'password') \gexec
+  become_user: postgres
+  changed_when: false
+  no_log: true
+
+- name: Provision application database
+  ansible.builtin.command:
+    argv: [psql, --set, "database={{ app_db_name }}", --set, "role={{ app_db_user }}", --dbname, postgres]
+    stdin: |
+      SELECT format('CREATE DATABASE %I OWNER %I', :'database', :'role')
+      WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = :'database') \gexec
+      SELECT format('ALTER DATABASE %I OWNER TO %I', :'database', :'role') \gexec
+  become_user: postgres
+  changed_when: false