The echo peer outlives a failed call instead of exiting

Peer's autoreply loop had no catch, so one failed poll or send to the relay
ended the process. The on-device reply case then waited out its 90 seconds
for an echo from a peer that was gone, which fits the one missed echo seen
in five full runs on 2026-09-28 (its log was lost, so not proven).

Each poll and each echo is now caught, logged to stderr with a timestamp
("poll failed, still answering: ..."), and the loop carries on. The
closing JSON adds an `errors` count. instrumented.sh already prints the
echo peer's log when a run fails, so a recurrence will say why.

Checked against a relay address that refuses connections: the old peer
exits 1 on the first poll with no result; the new one runs its full 8 s,
logs 4 failed polls and prints {"echoed":0,"errors":4}. Against relay1: 0
errors. Full on-device suite with the new peer: 10 of 10.

Harness only: interop/ is not shipped.

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

interop/src/main/kotlin/io/flamenet/interop/Peer.kt

@@ -120,15 +120,40 @@ object Peer {
                 val seconds = args.getOrNull(2)?.toIntOrNull() ?: 60
                 val deadline = System.currentTimeMillis() + seconds * 1000L
                 var replied = 0
+                var errors = 0
+                // One failed call is logged and outlived, not fatal. This loop
+                // used to have no catch at all, so a single dropped poll or send
+                // to the relay ended the process, and the on-device reply case
+                // waited out its 90 seconds for an echo from a peer that was no
+                // longer running. The log line is what the script prints when
+                // that case fails.
+                fun failed(
+                    what: String,
+                    e: Exception,
+                ) {
+                    errors += 1
+                    System.err.println("${java.time.Instant.now()} $what failed, still answering: $e")
+                }
                 while (System.currentTimeMillis() < deadline) {
-                    for (message in conversations.poll()) {
-                        conversations.send(message.fromUser, "echo: " + message.text)
-                        replied += 1
-                        System.err.println("echoed to ${message.fromUser}: ${message.text}")
+                    val received =
+                        try {
+                            conversations.poll()
+                        } catch (e: Exception) {
+                            failed("poll", e)
+                            emptyList()
+                        }
+                    for (message in received) {
+                        try {
+                            conversations.send(message.fromUser, "echo: " + message.text)
+                            replied += 1
+                            System.err.println("echoed to ${message.fromUser}: ${message.text}")
+                        } catch (e: Exception) {
+                            failed("echo to ${message.fromUser}", e)
+                        }
                     }
                     Thread.sleep(2000)
                 }
-                println(JSONObject().put("echoed", replied))
+                println(JSONObject().put("echoed", replied).put("errors", errors))
             }
 
             else -> {