add all crates: domain, protocol, application, client, adapters, ESP32 firmware

Server: domain (entities, value objects, ports), protocol (postcard wire types),
application (config service, data projection), adapters (config-memory, tcp-server),
bootstrap (composition root with fake data).

Client: client-domain (layout engine, render tree, HAL ports),
client-application (message handling, repaint commands),
adapters (tcp-client, display-terminal), client-desktop (end-to-end working).

ESP32: client-esp32 firmware with ILI9341 display over SPI, WiFi networking.
Display test verified on hardware — landscape orientation, text rendering works.

60 workspace tests, all passing.

crates/domain/src/ports/broadcast.rs

@@ -0,0 +1,17 @@
+use crate::entities::WidgetId;
+use crate::value_objects::{Layout, WidgetState};
+
+pub trait BroadcastPort {
+    type Error;
+
+    async fn push_screen_update(
+        &self,
+        layout: &Layout,
+        widgets: &[(WidgetId, WidgetState)],
+    ) -> Result<(), Self::Error>;
+
+    async fn push_data_update(
+        &self,
+        updates: &[(WidgetId, WidgetState)],
+    ) -> Result<(), Self::Error>;
+}