Add landing page, Hetzner labels, and Codeberg link

- Add default landing page (roles/caddy/templates/index.html.j2) deployed
  to empty caddy sites; adapted from YC/coming-soon by Steven Tang (MIT),
  with site domain and powered-by footer linking to codeberg.org/opennomad/linderhof
- Apply hcloud_labels to all Hetzner cloud and DNS resources; default to {}
  in role defaults for stacks without the variable defined
- Fix setup.sh: export stack_name so envsubst substitutes it in config.yml
- Add Codeberg repo link to README

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

roles/dns/defaults/main.yml

@@ -1,2 +1,3 @@
 ---
 dns_zones: []
+hcloud_labels: {}  # override in config.yml — see config.yml.setup for recommended labels

roles/dns/tasks/extra_mail_domain.yml

@@ -7,6 +7,7 @@
     ttl: 300
     records:
       - value: "{{ server_ip }}"
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
 
@@ -18,6 +19,7 @@
     ttl: 300
     records:
       - value: "10 {{ mail_hostname }}."
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
 
@@ -29,6 +31,7 @@
     ttl: 300
     records:
       - value: "{{ 'v=spf1 mx -all' | hetzner.hcloud.txt_record }}"
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
 
@@ -40,6 +43,7 @@
     ttl: 300
     records:
       - value: "{{ ('v=DMARC1; p=none; rua=mailto:dmarc@' + extra_domain) | hetzner.hcloud.txt_record }}"
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
 
@@ -51,6 +55,7 @@
     ttl: 300
     records:
       - value: "{{ dkim_keys[extra_domain] | hetzner.hcloud.txt_record }}"
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
   when: dkim_keys is defined and extra_domain in dkim_keys

roles/dns/tasks/main.yml

@@ -3,6 +3,7 @@
   hetzner.hcloud.zone:
     name: "{{ item.zone }}"
     mode: primary
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
   loop: "{{ dns_zones }}"
@@ -17,6 +18,7 @@
     type: "{{ item.1.type }}"
     ttl: "{{ item.1.ttl | default(300) }}"
     records: "{{ item.1.records }}"
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
   loop: "{{ dns_zones | subelements('records') }}"
@@ -29,6 +31,7 @@
   hetzner.hcloud.zone:
     name: "{{ item }}"
     mode: primary
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
   loop: "{{ mail_domains | difference([domain]) }}"
@@ -51,6 +54,7 @@
     ttl: 300
     records:
       - value: "{{ item.value | hetzner.hcloud.txt_record }}"
+    labels: "{{ hcloud_labels }}"
     api_token: "{{ hcloud_token }}"
     state: present
   loop: "{{ dkim_keys | default({}) | dict2items }}"