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/client-domain/src/ports/display.rs

@@ -0,0 +1,11 @@
+use crate::BoundingBox;
+
+pub trait DisplayPort {
+    type Error;
+
+    fn clear_region(&mut self, bounds: BoundingBox) -> Result<(), Self::Error>;
+    fn draw_text(&mut self, text: &str, x: u16, y: u16, bounds: BoundingBox) -> Result<(), Self::Error>;
+    fn draw_icon(&mut self, icon: &str, x: u16, y: u16) -> Result<(), Self::Error>;
+    fn fill_background(&mut self, bounds: BoundingBox) -> Result<(), Self::Error>;
+    fn flush(&mut self) -> Result<(), Self::Error>;
+}