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-application/tests/client_app_tests.rs

@@ -0,0 +1,154 @@
+use client_application::{ClientApp, RepaintCommand};
+use client_domain::BoundingBox;
+use protocol::{
+    ServerMessage, WidgetDescriptor,
+    WireDisplayHint, WireLayoutNode, WireContainerNode, WireLayoutChild,
+    WireDirection, WireSizing, WireWidgetState, WireKeyValue, WireValue,
+};
+
+fn screen() -> BoundingBox {
+    BoundingBox::screen(240, 320)
+}
+
+fn weather_descriptor(id: u16, temp: &str) -> WidgetDescriptor {
+    WidgetDescriptor {
+        id,
+        display_hint: WireDisplayHint::IconValue,
+        state: WireWidgetState {
+            data: vec![
+                WireKeyValue { key: "temperature".into(), value: WireValue::String(temp.into()) },
+            ],
+            error: None,
+        },
+    }
+}
+
+fn two_widget_layout() -> WireLayoutNode {
+    WireLayoutNode::Container(WireContainerNode {
+        direction: WireDirection::Row,
+        gap: 0,
+        padding: 0,
+        children: vec![
+            WireLayoutChild { sizing: WireSizing::Flex(1), node: WireLayoutNode::Leaf(1) },
+            WireLayoutChild { sizing: WireSizing::Flex(1), node: WireLayoutNode::Leaf(2) },
+        ],
+    })
+}
+
+#[test]
+fn screen_update_repaints_all_widgets() {
+    let mut app = ClientApp::new(screen());
+
+    let msg = ServerMessage::ScreenUpdate {
+        layout: two_widget_layout(),
+        widgets: vec![
+            weather_descriptor(1, "5.4°C"),
+            weather_descriptor(2, "20°C"),
+        ],
+    };
+
+    let repaints = app.handle_message(msg);
+
+    assert_eq!(repaints.len(), 2);
+    assert_eq!(repaints[0].widget_id, 1);
+    assert_eq!(repaints[0].bounds, BoundingBox::new(0, 0, 120, 320));
+    assert_eq!(repaints[1].widget_id, 2);
+    assert_eq!(repaints[1].bounds, BoundingBox::new(120, 0, 120, 320));
+}
+
+#[test]
+fn data_update_only_repaints_changed_widgets() {
+    let mut app = ClientApp::new(screen());
+
+    app.handle_message(ServerMessage::ScreenUpdate {
+        layout: two_widget_layout(),
+        widgets: vec![
+            weather_descriptor(1, "5.4°C"),
+            weather_descriptor(2, "20°C"),
+        ],
+    });
+
+    let repaints = app.handle_message(ServerMessage::DataUpdate {
+        widgets: vec![weather_descriptor(1, "6.1°C")],
+    });
+
+    assert_eq!(repaints.len(), 1);
+    assert_eq!(repaints[0].widget_id, 1);
+    assert_eq!(
+        repaints[0].state.data[0].value,
+        WireValue::String("6.1°C".into())
+    );
+}
+
+#[test]
+fn data_update_with_unchanged_data_produces_no_repaints() {
+    let mut app = ClientApp::new(screen());
+
+    app.handle_message(ServerMessage::ScreenUpdate {
+        layout: two_widget_layout(),
+        widgets: vec![
+            weather_descriptor(1, "5.4°C"),
+            weather_descriptor(2, "20°C"),
+        ],
+    });
+
+    let repaints = app.handle_message(ServerMessage::DataUpdate {
+        widgets: vec![weather_descriptor(1, "5.4°C")],
+    });
+
+    assert!(repaints.is_empty());
+}
+
+#[test]
+fn second_screen_update_repaints_all_widgets_with_new_layout() {
+    let mut app = ClientApp::new(screen());
+
+    app.handle_message(ServerMessage::ScreenUpdate {
+        layout: two_widget_layout(),
+        widgets: vec![
+            weather_descriptor(1, "5.4°C"),
+            weather_descriptor(2, "20°C"),
+        ],
+    });
+
+    let column_layout = WireLayoutNode::Container(WireContainerNode {
+        direction: WireDirection::Column,
+        gap: 0,
+        padding: 0,
+        children: vec![
+            WireLayoutChild { sizing: WireSizing::Flex(1), node: WireLayoutNode::Leaf(1) },
+            WireLayoutChild { sizing: WireSizing::Flex(1), node: WireLayoutNode::Leaf(2) },
+        ],
+    });
+
+    let repaints = app.handle_message(ServerMessage::ScreenUpdate {
+        layout: column_layout,
+        widgets: vec![
+            weather_descriptor(1, "5.4°C"),
+            weather_descriptor(2, "20°C"),
+        ],
+    });
+
+    assert_eq!(repaints.len(), 2);
+    assert_eq!(repaints[0].bounds, BoundingBox::new(0, 0, 240, 160));
+    assert_eq!(repaints[1].bounds, BoundingBox::new(0, 160, 240, 160));
+}
+
+#[test]
+fn data_update_before_screen_update_produces_no_repaints() {
+    let mut app = ClientApp::new(screen());
+
+    let repaints = app.handle_message(ServerMessage::DataUpdate {
+        widgets: vec![weather_descriptor(1, "5.4°C")],
+    });
+
+    assert!(repaints.is_empty());
+}
+
+#[test]
+fn heartbeat_produces_no_repaints() {
+    let mut app = ClientApp::new(screen());
+
+    let repaints = app.handle_message(ServerMessage::Heartbeat);
+    assert!(repaints.is_empty());
+}