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/src/data_projection.rs

@@ -0,0 +1,42 @@
+use std::collections::HashMap;
+use domain::{DataSourceId, Value, WidgetConfig, WidgetId, WidgetState};
+
+pub struct DataProjection {
+    current: HashMap<WidgetId, WidgetState>,
+}
+
+impl DataProjection {
+    pub fn new() -> Self {
+        Self {
+            current: HashMap::new(),
+        }
+    }
+
+    pub fn apply_poll_result(
+        &mut self,
+        data_source_id: DataSourceId,
+        raw: &Value,
+        widget_configs: &[WidgetConfig],
+    ) -> Vec<(WidgetId, WidgetState)> {
+        let mut changed = Vec::new();
+
+        for config in widget_configs {
+            if config.data_source_id != data_source_id {
+                continue;
+            }
+
+            let new_state = config.extract(raw);
+
+            let is_changed = self.current
+                .get(&config.id)
+                .map_or(true, |prev| *prev != new_state);
+
+            if is_changed {
+                self.current.insert(config.id, new_state.clone());
+                changed.push((config.id, new_state));
+            }
+        }
+
+        changed
+    }
+}