Drop the spent DeadAir clean-up and keep not-due skips off live updates (#196, #197)

The clean-up of DeadAir's old copies probed for its table on every open, and on
Postgres each failed probe is an ERROR in the server's log: 120 an hour from the
healthcheck alone. Production ran it already and is the only database.

A scan sent a not-due skip for each of ~1,535 feeds into a broadcast of 1,024,
so a page slow to read lagged and dropped events: 443 counted in five hours.
Nothing listening uses them; the terminal and the log still get them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ipc.rs

@@ -144,7 +144,12 @@ impl Emitter {
         // line per feed per tick for "not due yet" would push everything worth reading
         // out of the buffer within a few minutes.
         log_event(&e, self.tx.is_some());
-        if let Some(tx) = &self.tx {
+        // A feed not due changes nothing a listener shows, and a scan has one for nearly every
+        // feed: 1,500 at once overflowed the channel's 1,024 for a page slow to read (#197).
+        let routine = matches!(&e, Event::FeedSkip { reason, .. } if reason.starts_with("not due"));
+        if let Some(tx) = &self.tx
+            && !routine
+        {
             // An error here only means nobody is listening yet.
             let _ = tx.send(e.clone());
         }
@@ -362,6 +367,17 @@ pub async fn proxy(path: &Path, cmd: &Command) -> Result<()> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn a_feed_not_due_stays_off_the_live_updates() {
+        let (tx, mut rx) = broadcast::channel(4);
+        let out = Emitter::socket(tx, false);
+        for i in 0..10 {
+            out.emit(Event::FeedSkip { feed: format!("f{i}"), reason: "not due for 5m".into() });
+        }
+        out.emit(Event::FeedSkip { feed: "g".into(), reason: "not modified".into() });
+        assert!(matches!(rx.try_recv(), Ok(Event::FeedSkip { feed, .. }) if feed == "g"), "nothing missed");
+    }
+
     #[test]
     fn a_feed_that_moved_says_so_on_the_wire_and_in_words() {
         let e = Event::FeedMoved { feed: "x".into(), from: "http://a/f".into(), to: "https://a/f".into() };