rewire bootstrap with SQLite, HTTP API, and real polling

bootstrap: SQLite config, HTTP API on :3000, TCP on :2699, poll loops.
http-api: added serve() so bootstrap doesn't depend on axum directly.
polling: reads data sources from config, polls via http-json adapter,
pushes changed widgets to connected clients.

configure via API, e.g.:
  curl -X POST localhost:3000/api/data-sources -H 'Content-Type: application/json' -d '{...}'
  curl -X PUT localhost:3000/api/layout -H 'Content-Type: application/json' -d '{...}'

crates/adapters/rss/src/parser.rs

@@ -37,7 +37,7 @@ pub fn parse_rss(xml: &str) -> Result<Value, RssError> {
                 current_tag.clear();
             }
             Ok(Event::Text(e)) => {
-                let text = e.unescape().unwrap_or_default().to_string();
+                let text = String::from_utf8_lossy(e.as_ref()).to_string();
                 if !current_tag.is_empty() && !text.trim().is_empty() {
                     if let Some(item) = current_item.as_mut() {
                         item.insert(current_tag.clone(), Value::String(text));