Refactor DNS handling and add solo record support

- Added 'solo' flag support for A/AAAA, CNAME/MX/TXT, and SRV records in sys-dns-cloudflare-records.
- Simplified sys-svc-dns: removed NS management tasks and CLOUDFLARE_NAMESERVERS default.
- Renamed 03_apex.yml back to 02_apex.yml, adjusted AAAA task name.
- Updated web-app-bluesky DNS tasks: marked critical records with 'solo'.
- Updated web-app-mailu DNS tasks: removed cleanup block, enforced 'solo' on all records.
- Adjusted constructor stage to call domain_mappings with AUTO_BUILD_ALIASES parameter.

Conversation: https://chatgpt.com/share/68cd20d8-9ba8-800f-b070-f7294f072c40

roles/web-app-bluesky/tasks/03_dns.yml

@@ -26,6 +26,7 @@
         zone: "{{ BLUESKY_API_DOMAIN | to_zone }}"
         name: "{{ BLUESKY_API_DOMAIN }}"
         content: "{{ networks.internet.ip4 }}"
+        solo: true
         proxied: false
 
       - type: AAAA
@@ -33,6 +34,7 @@
         name: "{{ BLUESKY_API_DOMAIN }}"
         content: "{{ networks.internet.ip6 | default('') }}"
         proxied: false
+        solo: true
         state: "{{ (networks.internet.ip6 is defined and (networks.internet.ip6 | string) | length > 0) | ternary('present','absent') }}"
 
       # 2) Handle verification for primary handle (Apex)
@@ -40,9 +42,11 @@
         zone: "{{ PRIMARY_DOMAIN | to_zone }}"
         name: "_atproto.{{ PRIMARY_DOMAIN }}"
         value: '"did=did:web:{{ BLUESKY_API_DOMAIN }}"'
+        solo: true
 
       # 3) Web UI host (only if enabled)
       - type: A
+        solo: true
         zone: "{{ BLUESKY_WEB_DOMAIN | to_zone }}"
         name: "{{ BLUESKY_WEB_DOMAIN }}"
         content: "{{ networks.internet.ip4 }}"
@@ -50,6 +54,7 @@
         state: "{{ (BLUESKY_WEB_ENABLED | bool) | ternary('present','absent') }}"
 
       - type: AAAA
+        solo: true
         zone: "{{ BLUESKY_WEB_DOMAIN | to_zone }}"
         name: "{{ BLUESKY_WEB_DOMAIN }}"
         content: "{{ networks.internet.ip6 | default('') }}"
@@ -58,6 +63,7 @@
 
       # 4) Custom AppView host (only if you actually run one and it's not api.bsky.app)
       - type: A
+        solo: true
         zone: "{{ BLUESKY_VIEW_DOMAIN | to_zone }}"
         name: "{{ BLUESKY_VIEW_DOMAIN }}"
         content: "{{ networks.internet.ip4 }}"
@@ -65,6 +71,7 @@
         state: "{{ (BLUESKY_VIEW_ENABLED | bool) and (BLUESKY_VIEW_DOMAIN != 'api.bsky.app') | ternary('present','absent') }}"
 
       - type: AAAA
+        solo: true
         zone: "{{ BLUESKY_VIEW_DOMAIN | to_zone }}"
         name: "{{ BLUESKY_VIEW_DOMAIN }}"
         content: "{{ networks.internet.ip6 | default('') }}"