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/bootstrap/src/main.rs

@@ -7,8 +7,7 @@ use application::DataProjection;
 use config_sqlite::SqliteConfigStore;
 use http_api::AppState;
 use std::sync::Arc;
-use tcp_server::{TcpBroadcaster, TcpEventBus, run_tcp_server};
-use tokio::sync::Mutex;
+use tcp_server::{ClientTracker, TcpBroadcaster, TcpEventBus, run_tcp_server};
 use tracing::{error, info};
 
 #[tokio::main]
@@ -29,12 +28,16 @@ async fn main() -> Result<()> {
 
     let event_bus = Arc::new(TcpEventBus::new(64));
     let broadcaster = Arc::new(TcpBroadcaster::new(64));
-    let projection = Arc::new(Mutex::new(DataProjection::new()));
+    let projection = Arc::new(DataProjection::new());
+    let tracker = Arc::new(ClientTracker::new());
 
     let tcp_addr = cfg.tcp_addr.clone();
     let tcp_bc = broadcaster.clone();
+    let tcp_tracker = tracker.clone();
+    let tcp_config = config_store.clone();
+    let tcp_proj = projection.clone();
     tokio::spawn(async move {
-        if let Err(e) = run_tcp_server(&tcp_addr, tcp_bc).await {
+        if let Err(e) = run_tcp_server(&tcp_addr, tcp_bc, tcp_tracker, tcp_config, tcp_proj).await {
             error!(error = %e, "tcp server failed");
         }
     });
@@ -44,6 +47,10 @@ async fn main() -> Result<()> {
     let http_state = AppState {
         config: config_store.clone(),
         events: event_bus.clone(),
+        widget_states: projection.clone(),
+        broadcaster: broadcaster.clone(),
+        clients: tracker.clone(),
+        spa_dir: cfg.spa_dir,
     };
     tokio::spawn(async move {
         if let Err(e) = http_api::serve(&http_addr, http_state).await {