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/webhook.rs

@@ -0,0 +1,81 @@
+use crate::AppState;
+use axum::extract::{Path, State};
+use axum::http::StatusCode;
+use axum::response::Json;
+use domain::{BroadcastPort, ConfigRepository, EventPublisher, WidgetStateReader};
+
+type S<C, E, W, B, R> = State<AppState<C, E, W, B, R>>;
+
+pub async fn receive_webhook<C, E, W, B, R>(
+    State(state): S<C, E, W, B, R>,
+    Path(source_id): Path<u16>,
+    Json(body): Json<serde_json::Value>,
+) -> Result<StatusCode, (StatusCode, String)>
+where
+    C: ConfigRepository,
+    C::Error: std::fmt::Debug,
+    E: EventPublisher,
+    E::Error: std::fmt::Debug,
+    W: WidgetStateReader,
+    B: BroadcastPort,
+    B::Error: std::fmt::Debug,
+{
+    let source = state
+        .config
+        .get_data_source(source_id)
+        .await
+        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("{e:?}")))?
+        .ok_or((StatusCode::NOT_FOUND, "data source not found".into()))?;
+
+    if source.source_type != domain::DataSourceType::Webhook {
+        return Err((
+            StatusCode::BAD_REQUEST,
+            "data source is not a webhook type".into(),
+        ));
+    }
+
+    let raw = json_to_domain_value(body);
+    let widgets = state
+        .config
+        .list_widgets()
+        .await
+        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("{e:?}")))?;
+
+    let layout = state
+        .config
+        .get_layout()
+        .await
+        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("{e:?}")))?;
+
+    let changed = state
+        .widget_states
+        .apply_raw_data(source_id, &raw, &widgets)
+        .await;
+
+    if !changed.is_empty()
+        && let Some(l) = &layout
+    {
+        let _ = state.broadcaster.push_screen_update(l, &changed).await;
+    }
+
+    Ok(StatusCode::OK)
+}
+
+fn json_to_domain_value(json: serde_json::Value) -> domain::Value {
+    match json {
+        serde_json::Value::Null => domain::Value::Null,
+        serde_json::Value::Bool(b) => domain::Value::Bool(b),
+        serde_json::Value::Number(n) => domain::Value::Number(n.as_f64().unwrap_or(0.0)),
+        serde_json::Value::String(s) => domain::Value::String(s),
+        serde_json::Value::Array(arr) => {
+            domain::Value::Array(arr.into_iter().map(json_to_domain_value).collect())
+        }
+        serde_json::Value::Object(obj) => {
+            let map = obj
+                .into_iter()
+                .map(|(k, v)| (k, json_to_domain_value(v)))
+                .collect();
+            domain::Value::Object(map)
+        }
+    }
+}