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/application/tests/data_projection_tests.rs

@@ -0,0 +1,82 @@
+use std::collections::BTreeMap;
+use domain::{
+    DisplayHint, KeyMapping, Value, WidgetConfig, WidgetId, WidgetState,
+};
+use application::DataProjection;
+
+fn weather_widget() -> WidgetConfig {
+    WidgetConfig::new(
+        1,
+        "weather".into(),
+        DisplayHint::IconValue,
+        10,
+        vec![
+            KeyMapping { source_path: "$.temp".into(), target_key: "temperature".into() },
+            KeyMapping { source_path: "$.icon".into(), target_key: "icon".into() },
+        ],
+    )
+}
+
+fn weather_response(temp: f64) -> Value {
+    Value::Object(BTreeMap::from([
+        ("temp".into(), Value::Number(temp)),
+        ("icon".into(), Value::String("sunny".into())),
+    ]))
+}
+
+#[test]
+fn apply_poll_result_detects_new_widget_state() {
+    let mut projection = DataProjection::new();
+    let widgets = vec![weather_widget()];
+
+    let changed = projection.apply_poll_result(10, &weather_response(5.4), &widgets);
+
+    assert_eq!(changed.len(), 1);
+    assert_eq!(changed[0].0, 1);
+    assert_eq!(changed[0].1.data.get("temperature"), Some(&Value::Number(5.4)));
+}
+
+#[test]
+fn apply_poll_result_returns_empty_when_nothing_changed() {
+    let mut projection = DataProjection::new();
+    let widgets = vec![weather_widget()];
+
+    projection.apply_poll_result(10, &weather_response(5.4), &widgets);
+    let changed = projection.apply_poll_result(10, &weather_response(5.4), &widgets);
+
+    assert!(changed.is_empty());
+}
+
+#[test]
+fn apply_poll_result_detects_changed_value() {
+    let mut projection = DataProjection::new();
+    let widgets = vec![weather_widget()];
+
+    projection.apply_poll_result(10, &weather_response(5.4), &widgets);
+    let changed = projection.apply_poll_result(10, &weather_response(6.1), &widgets);
+
+    assert_eq!(changed.len(), 1);
+    assert_eq!(changed[0].1.data.get("temperature"), Some(&Value::Number(6.1)));
+}
+
+#[test]
+fn apply_poll_result_only_updates_widgets_bound_to_source() {
+    let mut projection = DataProjection::new();
+    let widgets = vec![
+        weather_widget(),
+        WidgetConfig::new(
+            2,
+            "portfolio".into(),
+            DisplayHint::KeyValue,
+            20,
+            vec![
+                KeyMapping { source_path: "$.value".into(), target_key: "amount".into() },
+            ],
+        ),
+    ];
+
+    let changed = projection.apply_poll_result(10, &weather_response(5.4), &widgets);
+
+    assert_eq!(changed.len(), 1);
+    assert_eq!(changed[0].0, 1);
+}