dashboard: list record types in the README's order (closes #226)

Each row of the Hostnames table listed a nameserver's record types in
the order Go happens to walk the record map, which changed from row to
row and on every page load, so two nameservers with the same records
looked different. formatRecords now sorts the types by their place in
the README's list (A, AAAA, CNAME, MX, TXT, SRV, CAA, NS); any other
type comes after them in alphabetical order. Values within a type were
already sorted by the resolver.

Model: opus-5-5

TODO.md

@@ -19,6 +19,8 @@ trial run of the finished image: https://git.eeqj.de/sneak/dnswatcher/issues/149
 
 # Completed Steps
 
+- 2026-10-02: the dashboard lists each nameserver's record types in one fixed
+  order, the README's, then any other type, not a random one (closes #226).
 - 2026-10-02: the dashboard and `/api/v1/status` show why a nameserver query or
   a certificate check failed, which only the state file showed (closes #225).
 - 2026-10-02: a name's CNAME is stored once per nameserver, not once per record