internal data sources (clock, static text), connection indicator, rendering fixes

DataSourceConfig refactored to enum: External/Clock/StaticText. Clock
generates formatted time via chrono, static text emits configured string.

ESP32: connection status indicator (green/red dot bottom-right), per-widget
clear before redraw, RenderEvent enum for local + server messages.

Polling uses DataUpdate instead of ScreenUpdate to avoid wiping widget state.
Empty mappings passthrough raw source data for internal sources.

crates/bootstrap/src/polling.rs

@@ -1,13 +1,16 @@
 use anyhow::Result;
 use application::DataProjection;
+use chrono::Utc;
+use chrono_tz::Tz;
 use config_sqlite::SqliteConfigStore;
 use domain::{
-    BroadcastPort, ConfigRepository, DataSource, DataSourcePort, DataSourceType, Value, WidgetState,
+    BroadcastPort, ConfigRepository, DataSource, DataSourceConfig, DataSourcePort, DataSourceType,
+    Value, WidgetState,
 };
 use http_json::HttpJsonAdapter;
 use media_adapter::MediaAdapter;
 use rss_adapter::RssAdapter;
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap};
 use std::sync::Arc;
 use std::time::Duration;
 use tcp_server::TcpBroadcaster;
@@ -117,14 +120,6 @@ async fn poll_loop(
             }
         };
 
-        let layout = match config.get_layout().await {
-            Ok(l) => l,
-            Err(e) => {
-                warn!(error = %e, "failed to fetch layout");
-                continue;
-            }
-        };
-
         let changed: Vec<(u16, WidgetState)> = projection
             .apply_poll_result(source.id, &result, &widgets)
             .await;
@@ -137,9 +132,7 @@ async fn poll_loop(
                     Some((*id, hint, state.clone()))
                 })
                 .collect();
-            if let Some(l) = &layout
-                && let Err(e) = broadcaster.push_screen_update(l, &with_hints).await
-            {
+            if let Err(e) = broadcaster.push_data_update(&with_hints).await {
                 warn!(error = %e, "failed to push update");
             }
             info!(source = %source.name, count = changed.len(), "pushed widget updates");
@@ -166,8 +159,33 @@ async fn poll_source(
             .poll(source)
             .await
             .map_err(|e| anyhow::anyhow!("{e}")),
+        DataSourceType::Clock => Ok(generate_clock(&source.config)),
+        DataSourceType::StaticText => Ok(generate_static_text(&source.config)),
         DataSourceType::Webhook => Err(anyhow::anyhow!(
             "webhook sources are push-based, not polled"
         )),
     }
 }
+
+fn generate_clock(config: &DataSourceConfig) -> Value {
+    let (fmt, tz_name) = match config {
+        DataSourceConfig::Clock { format, timezone } => (format.as_str(), timezone.as_str()),
+        _ => ("%H:%M:%S", "UTC"),
+    };
+    let tz: Tz = tz_name.parse().unwrap_or(chrono_tz::UTC);
+    let now = Utc::now().with_timezone(&tz);
+    let formatted = now.format(fmt).to_string();
+    let mut map = BTreeMap::new();
+    map.insert("time".into(), Value::String(formatted));
+    Value::Object(map)
+}
+
+fn generate_static_text(config: &DataSourceConfig) -> Value {
+    let text = match config {
+        DataSourceConfig::StaticText { text } => text.clone(),
+        _ => String::new(),
+    };
+    let mut map = BTreeMap::new();
+    map.insert("text".into(), Value::String(text));
+    Value::Object(map)
+}