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/src/client_app.rs

@@ -0,0 +1,110 @@
+use std::collections::HashMap;
+use domain::LayoutNode;
+use client_domain::{BoundingBox, LayoutEngine, RenderTree};
+use protocol::{
+    ServerMessage, WidgetDescriptor, WireDisplayHint, WireWidgetState, WireLayoutNode,
+};
+
+pub struct ClientApp {
+    screen: BoundingBox,
+    render_tree: Option<RenderTree>,
+    widget_states: HashMap<u16, (WireDisplayHint, WireWidgetState)>,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct RepaintCommand {
+    pub widget_id: u16,
+    pub bounds: BoundingBox,
+    pub display_hint: WireDisplayHint,
+    pub state: WireWidgetState,
+}
+
+impl ClientApp {
+    pub fn new(screen: BoundingBox) -> Self {
+        Self {
+            screen,
+            render_tree: None,
+            widget_states: HashMap::new(),
+        }
+    }
+
+    pub fn handle_message(&mut self, msg: ServerMessage) -> Vec<RepaintCommand> {
+        match msg {
+            ServerMessage::ScreenUpdate { layout, widgets } => {
+                self.handle_screen_update(layout, widgets)
+            }
+            ServerMessage::DataUpdate { widgets } => {
+                self.handle_data_update(widgets)
+            }
+            ServerMessage::Heartbeat => Vec::new(),
+        }
+    }
+
+    fn handle_screen_update(
+        &mut self,
+        wire_layout: WireLayoutNode,
+        widgets: Vec<WidgetDescriptor>,
+    ) -> Vec<RepaintCommand> {
+        let layout: LayoutNode = wire_layout.into();
+        let new_tree = LayoutEngine::compute(&layout, self.screen);
+
+        self.widget_states.clear();
+        for w in &widgets {
+            self.widget_states.insert(w.id, (w.display_hint.clone(), w.state.clone()));
+        }
+
+        let repaints = self.build_repaints_for_all(&new_tree);
+        self.render_tree = Some(new_tree);
+        repaints
+    }
+
+    fn handle_data_update(
+        &mut self,
+        widgets: Vec<WidgetDescriptor>,
+    ) -> Vec<RepaintCommand> {
+        let tree = match &self.render_tree {
+            Some(t) => t,
+            None => return Vec::new(),
+        };
+
+        let mut repaints = Vec::new();
+
+        for w in widgets {
+            let changed = self.widget_states
+                .get(&w.id)
+                .map_or(true, |(_, prev_state)| *prev_state != w.state);
+
+            if changed {
+                if let Some(bounds) = tree.get_widget_bounds(w.id) {
+                    repaints.push(RepaintCommand {
+                        widget_id: w.id,
+                        bounds: *bounds,
+                        display_hint: w.display_hint.clone(),
+                        state: w.state.clone(),
+                    });
+                }
+                self.widget_states.insert(w.id, (w.display_hint, w.state));
+            }
+        }
+
+        repaints
+    }
+
+    fn build_repaints_for_all(&self, tree: &RenderTree) -> Vec<RepaintCommand> {
+        let mut repaints = Vec::new();
+
+        for (id, (hint, state)) in &self.widget_states {
+            if let Some(bounds) = tree.get_widget_bounds(*id) {
+                repaints.push(RepaintCommand {
+                    widget_id: *id,
+                    bounds: *bounds,
+                    display_hint: hint.clone(),
+                    state: state.clone(),
+                });
+            }
+        }
+
+        repaints.sort_by_key(|r| r.widget_id);
+        repaints
+    }
+}

crates/client-application/src/lib.rs

@@ -0,0 +1,3 @@
+mod client_app;
+
+pub use client_app::{ClientApp, RepaintCommand};