docs: move dns automation from TODO.md to nixos-improvements.md

TODO.md

@@ -484,36 +484,6 @@ vault01.home.2rjus.net (10.69.13.19)
 
 ---
 
-### Phase 5: DNS Automation
-
-**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
-
----
-
 ### Phase 6: Integration Script
 
 **Goal:** Single command to create and deploy a new host