arch: split ConfigRepository, extract polling, consolidate conversions, decouple protocol

- Value↔JSON: From impls on domain Value behind `json` feature, delete 4 duplicate converters
- ConfigRepository split into ConfigRepository (12), UserRepository (3), WidgetStateCache (2)
- polling orchestration moved from bootstrap to application::polling_service
- WidgetRenderer in client-domain owns scroll/cache, both clients use it
- network loop consolidated into client-application::run_connection_loop
- protocol crate drops domain dep, Wire↔Domain conversions move to adapters

crates/adapters/http-api/src/routes/widgets.rs

@@ -126,32 +126,10 @@ where
 {
     match state.widget_states.get_widget_state(id).await {
         Some(ws) => {
-            let map: serde_json::Map<String, serde_json::Value> = ws
-                .data
-                .iter()
-                .map(|(k, v)| (k.clone(), domain_value_to_json(v)))
-                .collect();
+            let map: serde_json::Map<String, serde_json::Value> =
+                ws.data.iter().map(|(k, v)| (k.clone(), v.into())).collect();
             Ok(Json(serde_json::Value::Object(map)))
         }
         None => Err(StatusCode::NOT_FOUND),
     }
 }
-
-fn domain_value_to_json(v: &domain::Value) -> serde_json::Value {
-    match v {
-        domain::Value::Null => serde_json::Value::Null,
-        domain::Value::Bool(b) => serde_json::Value::Bool(*b),
-        domain::Value::Number(n) => serde_json::json!(n),
-        domain::Value::String(s) => serde_json::Value::String(s.clone()),
-        domain::Value::Array(arr) => {
-            serde_json::Value::Array(arr.iter().map(domain_value_to_json).collect())
-        }
-        domain::Value::Object(obj) => {
-            let map = obj
-                .iter()
-                .map(|(k, v)| (k.clone(), domain_value_to_json(v)))
-                .collect();
-            serde_json::Value::Object(map)
-        }
-    }
-}