fix(daemon): record the docker events failure, not only the recovery [P2]

The outer loop called set_err and dropped the result, so no docker_events=error line was
ever written while the reconnect did write docker_events=recovered. The events log could
therefore show a recovery from a failure it had never recorded, which contradicts its
documented contract of holding transitions in both directions. last_action.state was
correct throughout - this was the journal only.

Both branches now build the reason and share one report, matching the wording the periodic
reconcile already uses.

traffic_core/src/daemon.rs

@@ -89,21 +89,15 @@ pub fn run(cfg: Config) -> anyhow::Result<()> {
     let events_state = state.clone();
     thread::spawn(move || {
         loop {
-            match docker_events_loop(&events_cfg, &events_state) {
-                Ok(()) => {
-                    set_err(
-                        &events_state,
-                        "docker_events",
-                        "docker events stream ended, restarting".to_string(),
-                    );
-                }
-                Err(e) => {
-                    set_err(
-                        &events_state,
-                        "docker_events",
-                        format!("docker events loop crashed: {e}"),
-                    );
-                }
+            let reason = match docker_events_loop(&events_cfg, &events_state) {
+                Ok(()) => "docker events stream ended, restarting".to_string(),
+                Err(e) => format!("docker events loop crashed: {e}"),
+            };
+            // The reconnect writes its recovery, so the failure has to be written too. The
+            // journal is documented as holding transitions in both directions, and dropping
+            // this one left it showing a recovery from a failure it never recorded.
+            if set_err(&events_state, "docker_events", reason.clone()) {
+                append_event(&format!("docker_events=error error=\"{reason}\""));
             }
             thread::sleep(Duration::from_secs(10));
         }