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/application/src/data_projection.rs

@@ -1,9 +1,17 @@
-use domain::{DataSourceId, Value, WidgetConfig, WidgetId, WidgetState};
+use domain::{DataSourceId, Value, WidgetConfig, WidgetId, WidgetState, WidgetStateReader};
 use std::collections::HashMap;
+use tokio::sync::Mutex;
 
-#[derive(Default)]
 pub struct DataProjection {
-    current: HashMap<WidgetId, WidgetState>,
+    current: Mutex<HashMap<WidgetId, WidgetState>>,
+}
+
+impl Default for DataProjection {
+    fn default() -> Self {
+        Self {
+            current: Mutex::new(HashMap::new()),
+        }
+    }
 }
 
 impl DataProjection {
@@ -11,16 +19,17 @@ impl DataProjection {
         Self::default()
     }
 
-    pub fn get_state(&self, widget_id: WidgetId) -> Option<&WidgetState> {
-        self.current.get(&widget_id)
+    pub async fn get_state(&self, widget_id: WidgetId) -> Option<WidgetState> {
+        self.current.lock().await.get(&widget_id).cloned()
     }
 
-    pub fn apply_poll_result(
-        &mut self,
+    pub async fn apply_poll_result(
+        &self,
         data_source_id: DataSourceId,
         raw: &Value,
         widget_configs: &[WidgetConfig],
     ) -> Vec<(WidgetId, WidgetState)> {
+        let mut current = self.current.lock().await;
         let mut changed = Vec::new();
 
         for config in widget_configs {
@@ -30,13 +39,12 @@ impl DataProjection {
 
             let new_state = config.extract(raw);
 
-            let is_changed = self
-                .current
+            let is_changed = current
                 .get(&config.id)
                 .is_none_or(|prev| *prev != new_state);
 
             if is_changed {
-                self.current.insert(config.id, new_state.clone());
+                current.insert(config.id, new_state.clone());
                 changed.push((config.id, new_state));
             }
         }
@@ -44,3 +52,18 @@ impl DataProjection {
         changed
     }
 }
+
+impl WidgetStateReader for DataProjection {
+    async fn get_widget_state(&self, id: WidgetId) -> Option<WidgetState> {
+        self.get_state(id).await
+    }
+
+    async fn apply_raw_data(
+        &self,
+        source_id: u16,
+        raw: &Value,
+        widgets: &[WidgetConfig],
+    ) -> Vec<(WidgetId, WidgetState)> {
+        self.apply_poll_result(source_id, raw, widgets).await
+    }
+}