chore(release): v0.19.0

CHANGELOG.md

@@ -7,6 +7,17 @@ change type. Preview the next one with `ludic dev release --dry-run`.
 A released section may carry a hand-written summary paragraph above its groups
 (v0.2.0 has one); the generated bullets below it are not edited by hand.
 
+## v0.19.0 — 2026-09-17
+
+### Features
+
+- `Udp.*`: polled IPv4 datagrams - the transport under a game's own netcode. `Udp.open(port)`
+  binds a non-blocking socket (port 0 picks one, `Udp.port` says which), `Udp.send` sends one
+  datagram to an address and port, and `Udp.recv` drains what arrived without ever blocking;
+  `Udp.from_ip` / `Udp.from_port` name the sender. `Udp.ip` / `Udp.ip_text` convert addresses,
+  `Udp.resolve` looks a host name up and `Udp.local_ip` is the address a player on the same
+  network would dial. BSD sockets on macOS (`runtime/native/udp.ll`), Winsock on Windows
+  (`udp_win.ll`, linked with ws2_32), linked only into a program that uses `Udp.*`.
 ## v0.18.1 — 2026-09-16
 
 ### Fixes