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/domain/tests/widget_tests.rs

@@ -0,0 +1,110 @@
+use std::collections::BTreeMap;
+use domain::{DisplayHint, KeyMapping, Value, WidgetConfig};
+
+#[test]
+fn extract_applies_all_mappings_to_produce_widget_state() {
+    let config = WidgetConfig {
+        id: 1,
+        name: "weather".into(),
+        display_hint: DisplayHint::IconValue,
+        data_source_id: 1,
+        mappings: vec![
+            KeyMapping { source_path: "$.main.temp".into(), target_key: "temperature".into() },
+            KeyMapping { source_path: "$.weather[0].icon".into(), target_key: "icon".into() },
+        ],
+        max_data_size: 2048,
+    };
+
+    let raw = Value::Object(BTreeMap::from([
+        ("main".into(), Value::Object(BTreeMap::from([
+            ("temp".into(), Value::Number(5.4)),
+        ]))),
+        ("weather".into(), Value::Array(vec![
+            Value::Object(BTreeMap::from([
+                ("icon".into(), Value::String("cloud_rain".into())),
+            ])),
+        ])),
+    ]));
+
+    let state = config.extract(&raw);
+
+    assert_eq!(state.data.get("temperature"), Some(&Value::Number(5.4)));
+    assert_eq!(state.data.get("icon"), Some(&Value::String("cloud_rain".into())));
+    assert_eq!(state.error, None);
+}
+
+#[test]
+fn extract_truncates_string_values_exceeding_max_data_size() {
+    let long_text = "a".repeat(3000);
+    let config = WidgetConfig {
+        id: 1,
+        name: "news".into(),
+        display_hint: DisplayHint::TextBlock,
+        data_source_id: 1,
+        mappings: vec![
+            KeyMapping { source_path: "$.text".into(), target_key: "body".into() },
+        ],
+        max_data_size: 100,
+    };
+
+    let raw = Value::Object(BTreeMap::from([
+        ("text".into(), Value::String(long_text)),
+    ]));
+
+    let state = config.extract(&raw);
+    match state.data.get("body") {
+        Some(Value::String(s)) => assert!(s.len() <= 100),
+        other => panic!("expected truncated string, got {:?}", other),
+    }
+}
+
+#[test]
+fn extract_respects_max_data_size_across_total_state() {
+    let config = WidgetConfig {
+        id: 1,
+        name: "big".into(),
+        display_hint: DisplayHint::TextBlock,
+        data_source_id: 1,
+        mappings: vec![
+            KeyMapping { source_path: "$.a".into(), target_key: "a".into() },
+            KeyMapping { source_path: "$.b".into(), target_key: "b".into() },
+            KeyMapping { source_path: "$.c".into(), target_key: "c".into() },
+        ],
+        max_data_size: 50,
+    };
+
+    let raw = Value::Object(BTreeMap::from([
+        ("a".into(), Value::String("x".repeat(20))),
+        ("b".into(), Value::String("y".repeat(20))),
+        ("c".into(), Value::String("z".repeat(20))),
+    ]));
+
+    let state = config.extract(&raw);
+    let total: usize = state.data.values().map(|v| v.estimated_size()).sum();
+    assert!(total <= 50, "total size {total} exceeds max 50");
+}
+
+#[test]
+fn extract_skips_mappings_that_dont_match() {
+    let config = WidgetConfig {
+        id: 1,
+        name: "weather".into(),
+        display_hint: DisplayHint::IconValue,
+        data_source_id: 1,
+        mappings: vec![
+            KeyMapping { source_path: "$.temp".into(), target_key: "temperature".into() },
+            KeyMapping { source_path: "$.missing".into(), target_key: "gone".into() },
+        ],
+        max_data_size: 2048,
+    };
+
+    let raw = Value::Object(BTreeMap::from([
+        ("temp".into(), Value::Number(5.4)),
+    ]));
+
+    let state = config.extract(&raw);
+
+    assert_eq!(state.data.len(), 1);
+    assert_eq!(state.data.get("temperature"), Some(&Value::Number(5.4)));
+    assert_eq!(state.data.get("gone"), None);
+}