feat(deploy): Ansible provisioning for prod hosts (Stage 18)

Idempotent playbooks under deploy/ansible/ prepare both production hosts:
docker-ce + compose plugin, a non-sudo deploy service account holding the CI
deploy key, key-only sshd, default-deny ufw, fail2ban, unattended upgrades and
chrony. The main host also opens 80/443/9443 and creates the external edge
network; the tg host verifies direct Bot API egress (the no-VPN assumption).

The application is deployed separately by the prod-deploy workflow (later
phase), running as the deploy account this playbook provisions.

deploy/ansible/roles/common/handlers/main.yml

@@ -0,0 +1,15 @@
+---
+- name: restart docker
+  ansible.builtin.service:
+    name: docker
+    state: restarted
+
+- name: reload sshd
+  ansible.builtin.service:
+    name: ssh
+    state: reloaded
+
+- name: restart fail2ban
+  ansible.builtin.service:
+    name: fail2ban
+    state: restarted

deploy/ansible/roles/common/tasks/main.yml

@@ -0,0 +1,167 @@
+---
+# Common baseline applied to both prod hosts: Docker engine, a non-sudo deploy
+# service account, SSH hardening, a default-deny firewall, fail2ban, unattended
+# security upgrades and time sync. Every task is idempotent.
+
+- name: Install base packages
+  ansible.builtin.apt:
+    name:
+      - ca-certificates
+      - curl
+      - gnupg
+      - ufw
+      - fail2ban
+      - unattended-upgrades
+      - chrony
+    state: present
+    update_cache: true
+    cache_valid_time: 3600
+
+# --- Docker engine (official repo; trixie is published upstream) ---------------
+
+- name: Create apt keyring directory
+  ansible.builtin.file:
+    path: /etc/apt/keyrings
+    state: directory
+    mode: "0755"
+
+- name: Install Docker apt GPG key
+  ansible.builtin.get_url:
+    url: https://download.docker.com/linux/debian/gpg
+    dest: /etc/apt/keyrings/docker.asc
+    mode: "0644"
+
+- name: Add Docker apt repository
+  ansible.builtin.apt_repository:
+    repo: >-
+      deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.asc]
+      https://download.docker.com/linux/debian {{ ansible_distribution_release }} stable
+    filename: docker
+    state: present
+
+- name: Install Docker engine and the compose plugin
+  ansible.builtin.apt:
+    name:
+      - docker-ce
+      - docker-ce-cli
+      - containerd.io
+      - docker-buildx-plugin
+      - docker-compose-plugin
+    state: present
+    update_cache: true
+
+- name: Configure the Docker daemon (live-restore + log rotation)
+  ansible.builtin.template:
+    src: daemon.json.j2
+    dest: /etc/docker/daemon.json
+    mode: "0644"
+  notify: restart docker
+
+- name: Enable and start Docker
+  ansible.builtin.service:
+    name: docker
+    enabled: true
+    state: started
+
+# --- Deploy service account ----------------------------------------------------
+
+- name: Create the deploy service account
+  ansible.builtin.user:
+    name: "{{ deploy_user }}"
+    groups: docker
+    append: true
+    shell: /bin/bash
+    create_home: true
+
+- name: Ensure the deploy .ssh directory
+  ansible.builtin.file:
+    path: "/home/{{ deploy_user }}/.ssh"
+    state: directory
+    owner: "{{ deploy_user }}"
+    group: "{{ deploy_user }}"
+    mode: "0700"
+
+- name: Authorize the CI deploy SSH key (exclusive)
+  ansible.builtin.copy:
+    dest: "/home/{{ deploy_user }}/.ssh/authorized_keys"
+    content: "{{ deploy_ci_pubkey }}\n"
+    owner: "{{ deploy_user }}"
+    group: "{{ deploy_user }}"
+    mode: "0600"
+
+# --- SSH hardening -------------------------------------------------------------
+
+- name: Harden sshd (key-only auth)
+  ansible.builtin.template:
+    src: sshd-hardening.conf.j2
+    dest: /etc/ssh/sshd_config.d/10-scrabble-hardening.conf
+    mode: "0644"
+    validate: sshd -t -f %s
+  notify: reload sshd
+
+# --- Firewall (default deny incoming) ------------------------------------------
+# SSH is allowed before the policy flips so enabling ufw never locks us out.
+
+- name: Allow SSH through the firewall
+  community.general.ufw:
+    rule: allow
+    name: OpenSSH
+
+- name: Default-deny incoming, allow outgoing
+  community.general.ufw:
+    direction: "{{ item.direction }}"
+    policy: "{{ item.policy }}"
+  loop:
+    - { direction: incoming, policy: deny }
+    - { direction: outgoing, policy: allow }
+
+- name: Enable the firewall
+  community.general.ufw:
+    state: enabled
+
+# --- fail2ban ------------------------------------------------------------------
+
+- name: Configure the fail2ban sshd jail
+  ansible.builtin.template:
+    src: jail.local.j2
+    dest: /etc/fail2ban/jail.local
+    mode: "0644"
+  notify: restart fail2ban
+
+- name: Enable and start fail2ban
+  ansible.builtin.service:
+    name: fail2ban
+    enabled: true
+    state: started
+
+# --- Unattended security upgrades + time sync ----------------------------------
+
+- name: Enable unattended upgrades
+  ansible.builtin.copy:
+    dest: /etc/apt/apt.conf.d/20auto-upgrades
+    mode: "0644"
+    content: |
+      APT::Periodic::Update-Package-Lists "1";
+      APT::Periodic::Unattended-Upgrade "1";
+
+- name: Enable and start chrony
+  ansible.builtin.service:
+    name: chrony
+    enabled: true
+    state: started
+
+# --- Deploy directories --------------------------------------------------------
+
+- name: Create the scrabble base directories
+  ansible.builtin.file:
+    path: "{{ scrabble_base_dir }}/{{ item }}"
+    state: directory
+    owner: "{{ deploy_user }}"
+    group: "{{ deploy_user }}"
+    mode: "0750"
+  loop:
+    - ""
+    - config
+    - certs
+    - dumps
+    - images

deploy/ansible/roles/common/templates/daemon.json.j2

@@ -0,0 +1,8 @@
+{
+  "live-restore": true,
+  "log-driver": "json-file",
+  "log-opts": {
+    "max-size": "{{ docker_log_max_size }}",
+    "max-file": "{{ docker_log_max_file }}"
+  }
+}

deploy/ansible/roles/common/templates/jail.local.j2

@@ -0,0 +1,9 @@
+# Managed by Ansible (deploy/ansible).
+[DEFAULT]
+bantime = 1h
+findtime = 10m
+maxretry = 5
+backend = systemd
+
+[sshd]
+enabled = true

deploy/ansible/roles/common/templates/sshd-hardening.conf.j2

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+# Managed by Ansible (deploy/ansible). Key-only authentication.
+# root stays reachable by key (prohibit-password) for provisioning re-runs.
+PasswordAuthentication no
+PermitRootLogin prohibit-password
+PubkeyAuthentication yes
+KbdInteractiveAuthentication no