docs: move dns-automation plan to completed

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

docs/plans/nixos-improvements.md

@@ -2,30 +2,6 @@
 
 This document contains planned improvements to the NixOS infrastructure that are not directly part of the automated deployment pipeline.
 
-## DNS Automation
+## Completed
 
-**Goal:** Automatically generate DNS entries from host configurations
-
-**Approach:** Leverage Nix to generate zone file entries from flake host configurations
-
-Since most hosts use static IPs defined in their NixOS configurations, we can extract this information and automatically generate A records. This keeps DNS in sync with the actual host configs.
-
-**Tasks:**
-- [ ] Add optional CNAME field to host configurations
-  - [ ] Add `networking.cnames = [ "alias1" "alias2" ]` or similar option
-  - [ ] Document in host configuration template
-- [ ] Create Nix function to extract DNS records from all hosts
-  - [ ] Parse each host's `networking.hostName` and IP configuration
-  - [ ] Collect any defined CNAMEs
-  - [ ] Generate zone file fragment with A and CNAME records
-- [ ] Integrate auto-generated records into zone files
-  - [ ] Keep manual entries separate (for non-flake hosts/services)
-  - [ ] Include generated fragment in main zone file
-  - [ ] Add comments showing which records are auto-generated
-- [ ] Update zone file serial number automatically
-- [ ] Test zone file validity after generation
-- [ ] Either:
-  - [ ] Automatically trigger DNS server reload (Ansible)
-  - [ ] Or document manual step: merge to master, run upgrade on ns1/ns2
-
-**Deliverable:** DNS A records and CNAMEs automatically generated from host configs
+- [DNS Automation](completed/dns-automation.md) - Automatically generate DNS entries from host configurations