huskies: merge 1200 story Low-disk warning: the fleet tells the operator before the disk takes it down

server/src/startup/tick_loop.rs

@@ -183,9 +183,15 @@ pub(crate) fn spawn_tick_loop(
         })
         .unwrap_or((30, std::time::Duration::from_secs(4 * 3600)));
 
+    let disk_watch_host_id =
+        std::env::var("HOSTNAME").unwrap_or_else(|_| "unknown-host".to_string());
+    let disk_watch_watcher_tx = agents.watcher_tx();
+    let disk_watch_status = agents.status_broadcaster();
+
     tokio::spawn(async move {
         let mut interval = tokio::time::interval(std::time::Duration::from_secs(1));
         let mut tick_count: u64 = 0;
+        let mut disk_watch_state = service::disk_watch::DiskWatchState::default();
         loop {
             interval.tick().await;
             tick_count = tick_count.wrapping_add(1);
@@ -218,6 +224,25 @@ pub(crate) fn spawn_tick_loop(
                 agents.reap_stale_merge_jobs();
             }
 
+            // Low-disk-space watchdog (story 1200): check free space on the
+            // project workspace filesystem every 30 ticks (~30s) and emit a
+            // rate-limited warn/critical notification, or a recovery notice.
+            if tick_count.is_multiple_of(30)
+                && let Some(ref r) = root
+            {
+                let disk_config = config::ProjectConfig::load(r)
+                    .map(|c| c.disk_watch)
+                    .unwrap_or_default();
+                service::disk_watch::io::check_and_notify(
+                    r,
+                    &disk_config,
+                    &mut disk_watch_state,
+                    &disk_watch_watcher_tx,
+                    &disk_watch_status,
+                    &disk_watch_host_id,
+                );
+            }
+
             // Periodic reconciler: converge subscriber side effects so that
             // Lagged broadcast events never leave state permanently diverged.
             if tick_count.is_multiple_of(reconcile_interval)