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/value_tests.rs

@@ -0,0 +1,77 @@
+use std::collections::BTreeMap;
+use domain::Value;
+
+#[test]
+fn estimated_size_of_string_is_its_byte_length() {
+    let v = Value::String("hello".into());
+    assert_eq!(v.estimated_size(), 5);
+}
+
+#[test]
+fn estimated_size_of_number_is_8_bytes() {
+    assert_eq!(Value::Number(3.14).estimated_size(), 8);
+}
+
+#[test]
+fn estimated_size_of_null_and_bool_is_1() {
+    assert_eq!(Value::Null.estimated_size(), 1);
+    assert_eq!(Value::Bool(true).estimated_size(), 1);
+}
+
+#[test]
+fn estimated_size_of_nested_structure_sums_recursively() {
+    let v = Value::Object(BTreeMap::from([
+        ("key".into(), Value::String("value".into())),
+        ("num".into(), Value::Number(1.0)),
+    ]));
+    assert_eq!(v.estimated_size(), 19);
+}
+
+#[test]
+fn estimated_size_of_array_sums_elements() {
+    let v = Value::Array(vec![
+        Value::String("abc".into()),
+        Value::Number(1.0),
+    ]);
+    assert_eq!(v.estimated_size(), 11);
+}
+
+#[test]
+fn get_path_returns_none_for_missing_key() {
+    let data = Value::Object(BTreeMap::from([
+        ("main".into(), Value::Number(1.0)),
+    ]));
+    assert_eq!(data.get_path("$.missing"), None);
+}
+
+#[test]
+fn get_path_returns_none_when_traversing_non_object() {
+    let data = Value::Object(BTreeMap::from([
+        ("temp".into(), Value::Number(5.4)),
+    ]));
+    assert_eq!(data.get_path("$.temp.nested"), None);
+}
+
+#[test]
+fn get_path_accesses_array_by_index() {
+    let data = Value::Object(BTreeMap::from([
+        ("items".into(), Value::Array(vec![
+            Value::String("first".into()),
+            Value::String("second".into()),
+        ])),
+    ]));
+    assert_eq!(
+        data.get_path("$.items[1]"),
+        Some(&Value::String("second".into()))
+    );
+}
+
+#[test]
+fn get_path_traverses_nested_object() {
+    let data = Value::Object(BTreeMap::from([
+        ("main".into(), Value::Object(BTreeMap::from([
+            ("temp".into(), Value::Number(5.4)),
+        ]))),
+    ]));
+    assert_eq!(data.get_path("$.main.temp"), Some(&Value::Number(5.4)));
+}