Initial commit: nult - Ansible deployment toolkit

Merged from veridion-gitea and veridion-act-runner-gitea repos.

nult (Null-T) - instant teleportation from Strugatsky's Noon Universe.
Like Null-T, this toolkit instantly deploys infrastructure.

Roles:
- gitea: Gitea server with PostgreSQL (Docker Compose)
- act_runner: Gitea Actions runner

Playbooks:
- gitea.yml: Deploy Gitea server
- act-runner.yml: Deploy Act Runner
- site.yml: Deploy all services

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

roles/act_runner/tasks/config.yml

@@ -0,0 +1,56 @@
+---
+# =============================================================================
+# Gitea Act Runner - Configuration and Registration
+# =============================================================================
+#
+# Deploys the runner configuration and registers with Gitea.
+# Registration is idempotent: only runs if .runner file doesn't exist.
+#
+# The .runner file contains the runner's identity after registration.
+# DO NOT DELETE this file or re-registration will be required.
+#
+# =============================================================================
+
+# Deploy configuration file from template.
+- name: Deploy act_runner configuration
+  ansible.builtin.template:
+    src: config.yaml.j2
+    dest: "{{ act_runner_config_dir }}/config.yaml"
+    owner: "{{ act_runner_user }}"
+    group: "{{ act_runner_group }}"
+    mode: '0640'  # Restrictive: contains secrets
+  notify: Restart act_runner
+
+# Check if runner is already registered.
+# The .runner file is created during registration and persists.
+- name: Check if runner is already registered
+  ansible.builtin.stat:
+    path: "{{ act_runner_home }}/.runner"
+  register: act_runner_runner_file
+
+# Register the runner with Gitea (only if not already registered).
+# This is a one-time operation that creates the .runner file.
+- name: Register runner with Gitea
+  ansible.builtin.command:
+    cmd: >-
+      {{ act_runner_bin_path }} register
+      --no-interactive
+      --config {{ act_runner_config_dir }}/config.yaml
+      --instance {{ gitea_instance_url }}
+      --token {{ act_runner_token }}
+      --name {{ act_runner_name }}
+      --labels {{ act_runner_labels | join(',') }}
+    chdir: "{{ act_runner_home }}"
+  become: true
+  become_user: "{{ act_runner_user }}"
+  when: not act_runner_runner_file.stat.exists
+  register: act_runner_registration_result
+  changed_when: act_runner_registration_result.rc == 0
+  # Don't show token in logs
+  no_log: true
+
+# Display registration result (without sensitive data).
+- name: Display registration status
+  ansible.builtin.debug:
+    msg: >-
+      Runner registration: {{ 'NEW - registered successfully' if act_runner_registration_result.changed | default(false) else 'EXISTING - already registered' }}