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/support/mod.rs

@@ -0,0 +1,126 @@
+use std::cell::RefCell;
+use std::collections::HashMap;
+use domain::{
+    ConfigRepository, EventPublisher,
+    DataSource, DataSourceId, Layout, LayoutPreset, LayoutPresetId,
+    WidgetConfig, WidgetId, DomainEvent,
+};
+
+pub struct InMemoryConfigRepository {
+    pub widgets: RefCell<HashMap<WidgetId, WidgetConfig>>,
+    pub data_sources: RefCell<HashMap<DataSourceId, DataSource>>,
+    pub layout: RefCell<Option<Layout>>,
+    pub presets: RefCell<HashMap<LayoutPresetId, LayoutPreset>>,
+}
+
+impl InMemoryConfigRepository {
+    pub fn new() -> Self {
+        Self {
+            widgets: RefCell::new(HashMap::new()),
+            data_sources: RefCell::new(HashMap::new()),
+            layout: RefCell::new(None),
+            presets: RefCell::new(HashMap::new()),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Never;
+
+impl std::fmt::Display for Never {
+    fn fmt(&self, _: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        unreachable!()
+    }
+}
+
+impl ConfigRepository for InMemoryConfigRepository {
+    type Error = Never;
+
+    async fn get_widget(&self, id: WidgetId) -> Result<Option<WidgetConfig>, Self::Error> {
+        Ok(self.widgets.borrow().get(&id).cloned())
+    }
+
+    async fn list_widgets(&self) -> Result<Vec<WidgetConfig>, Self::Error> {
+        Ok(self.widgets.borrow().values().cloned().collect())
+    }
+
+    async fn save_widget(&self, config: &WidgetConfig) -> Result<(), Self::Error> {
+        self.widgets.borrow_mut().insert(config.id, config.clone());
+        Ok(())
+    }
+
+    async fn delete_widget(&self, id: WidgetId) -> Result<(), Self::Error> {
+        self.widgets.borrow_mut().remove(&id);
+        Ok(())
+    }
+
+    async fn get_data_source(&self, id: DataSourceId) -> Result<Option<DataSource>, Self::Error> {
+        Ok(self.data_sources.borrow().get(&id).cloned())
+    }
+
+    async fn list_data_sources(&self) -> Result<Vec<DataSource>, Self::Error> {
+        Ok(self.data_sources.borrow().values().cloned().collect())
+    }
+
+    async fn save_data_source(&self, source: &DataSource) -> Result<(), Self::Error> {
+        self.data_sources.borrow_mut().insert(source.id, source.clone());
+        Ok(())
+    }
+
+    async fn delete_data_source(&self, id: DataSourceId) -> Result<(), Self::Error> {
+        self.data_sources.borrow_mut().remove(&id);
+        Ok(())
+    }
+
+    async fn get_layout(&self) -> Result<Option<Layout>, Self::Error> {
+        Ok(self.layout.borrow().clone())
+    }
+
+    async fn save_layout(&self, layout: &Layout) -> Result<(), Self::Error> {
+        *self.layout.borrow_mut() = Some(layout.clone());
+        Ok(())
+    }
+
+    async fn get_preset(&self, id: LayoutPresetId) -> Result<Option<LayoutPreset>, Self::Error> {
+        Ok(self.presets.borrow().get(&id).cloned())
+    }
+
+    async fn list_presets(&self) -> Result<Vec<LayoutPreset>, Self::Error> {
+        Ok(self.presets.borrow().values().cloned().collect())
+    }
+
+    async fn save_preset(&self, preset: &LayoutPreset) -> Result<(), Self::Error> {
+        self.presets.borrow_mut().insert(preset.id, preset.clone());
+        Ok(())
+    }
+
+    async fn delete_preset(&self, id: LayoutPresetId) -> Result<(), Self::Error> {
+        self.presets.borrow_mut().remove(&id);
+        Ok(())
+    }
+}
+
+pub struct InMemoryEventPublisher {
+    pub events: RefCell<Vec<DomainEvent>>,
+}
+
+impl InMemoryEventPublisher {
+    pub fn new() -> Self {
+        Self {
+            events: RefCell::new(Vec::new()),
+        }
+    }
+
+    pub fn emitted(&self) -> Vec<DomainEvent> {
+        self.events.borrow().clone()
+    }
+}
+
+impl EventPublisher for InMemoryEventPublisher {
+    type Error = Never;
+
+    async fn publish(&self, event: DomainEvent) -> Result<(), Self::Error> {
+        self.events.borrow_mut().push(event);
+        Ok(())
+    }
+}