per-source polling, initial client state, webhook, preview, client tracking

- per-source poll intervals: spawn task per source with own interval,
  manager re-checks sources every 30s for add/remove
- initial screen update on TCP connect: send layout + widget states
- client tracking: ClientRegistry port, GET /api/clients, dashboard list
- webhook adapter: POST /api/webhook/{source_id} feeds data into projection
- widget preview: GET /api/widgets/{id}/preview returns current state
- serve SPA from Axum: ServeDir + index.html fallback via KFRAME_SPA_DIR
- layout builder delete confirmation with AlertDialog
- form validation: required fields disable save button
- guide page at /guide
- fix architecture: ClientDto to api-types, ClientRegistry + WidgetStateReader
  ports in domain, DataProjection has internal Mutex, no adapter cross-deps
- ESP32: full screen clear on layout change (stale pixel fix)

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

@@ -6,11 +6,13 @@ use axum::{
     http::StatusCode,
     response::Json,
 };
-use domain::{ConfigRepository, EventPublisher};
+use domain::{ConfigRepository, EventPublisher, WidgetStateReader};
 
-type S<C, E> = State<AppState<C, E>>;
+type S<C, E, W, B, R> = State<AppState<C, E, W, B, R>>;
 
-pub async fn list_widgets<C, E>(State(state): S<C, E>) -> Result<Json<Vec<WidgetDto>>, StatusCode>
+pub async fn list_widgets<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
+) -> Result<Json<Vec<WidgetDto>>, StatusCode>
 where
     C: ConfigRepository,
     C::Error: std::fmt::Debug,
@@ -25,8 +27,8 @@ where
     Ok(Json(widgets.iter().map(WidgetDto::from).collect()))
 }
 
-pub async fn get_widget<C, E>(
-    State(state): S<C, E>,
+pub async fn get_widget<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
     Path(id): Path<u16>,
 ) -> Result<Json<WidgetDto>, StatusCode>
 where
@@ -46,8 +48,8 @@ where
     }
 }
 
-pub async fn create_widget<C, E>(
-    State(state): S<C, E>,
+pub async fn create_widget<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
     Json(body): Json<CreateWidgetDto>,
 ) -> Result<StatusCode, (StatusCode, String)>
 where
@@ -66,8 +68,8 @@ where
     Ok(StatusCode::CREATED)
 }
 
-pub async fn update_widget<C, E>(
-    State(state): S<C, E>,
+pub async fn update_widget<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
     Path(_id): Path<u16>,
     Json(body): Json<CreateWidgetDto>,
 ) -> Result<StatusCode, (StatusCode, String)>
@@ -87,8 +89,8 @@ where
     Ok(StatusCode::OK)
 }
 
-pub async fn delete_widget<C, E>(
-    State(state): S<C, E>,
+pub async fn delete_widget<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
     Path(id): Path<u16>,
 ) -> Result<StatusCode, StatusCode>
 where
@@ -103,3 +105,46 @@ where
         .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
     Ok(StatusCode::NO_CONTENT)
 }
+
+pub async fn preview_widget<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
+    Path(id): Path<u16>,
+) -> Result<Json<serde_json::Value>, StatusCode>
+where
+    C: ConfigRepository,
+    C::Error: std::fmt::Debug,
+    E: EventPublisher,
+    E::Error: std::fmt::Debug,
+    W: WidgetStateReader,
+{
+    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();
+            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)
+        }
+    }
+}