milestone 18: collapse duplicated infrastructure into shared listener core, crud list helper, resource shells, transport race, name and line helpers, ui modules

specs/milestone-10.md

@@ -286,7 +286,10 @@ store-deinit and the refs==0 assert holds. `dot_alpn` (["dot"]) lives in app.zig
 Deviation: `doh_server.serve` module entry is NOT used — it constructs the DohServer in
 its own task frame, so WebState could never get the pointer the `nxdns_doh_server_*`
 family needs; both listeners bind in app.zig's frame instead (tcp_server style).
-`doh_server.serve` remains as unused pub API. metrics.zig: `DohListenerSample`
+`doh_server.serve` remains as unused pub API. **Superseded by milestone-18 ruling 1: the
+unused `doh_server.serve` is deleted. Nothing ever called it, and a dead second
+composition path over the listener core is exactly the divergence that milestone
+collapsed. app.zig's in-frame bind is now the only way DoH comes up.** metrics.zig: `DohListenerSample`
 (ruling-10 four + `bad_requests`); DoT renders `dot_server.StatsSnapshot` directly;
 accept-side counters stay off the exposition; unwired listeners omit the families.
 WebState gains `doh_listener`/`dot_listener` optional pointers. build.zig (out of