fix(icom): give up on the quiet CI-V stream after 15 s, not 30

The capture settled it: the 7760 keeps the transport chatting (pings answered,
no socket error, no loss) while CI-V data simply stops, the in-place reopen is
ignored, and only a fresh session brings it back. So: one reopen attempt at
10 s — kept, it is free and the log will say if a firmware ever honours it —
and at 15 s the link is failed deliberately so the manager rebuilds it,
halving the outage. Also: the recovered-acknowledgement now sits on the DATA
packet, not on any packet — pings were toggling the detector, 160 reopens in
thirty seconds all logged as recoveries that never happened.

internal/cat/icomnet.go

@@ -372,6 +372,7 @@ func (n *icomNet) civPump() {
 	lastScope := time.Time{} // scope frames within those
 	var lastErr error
 	quietSaid := false
+	gaveUp := false
 	for {
 		select {
 		case <-n.done:
@@ -386,10 +387,6 @@ func (n *icomNet) civPump() {
 			}
 		}
 		if err == nil && k >= 16 {
-			if quietSaid {
-				debugLog.Printf("icom net: CI-V replies are back after %s", time.Since(lastData).Round(time.Second))
-				quietSaid = false
-			}
 			lastPkt = time.Now()
 			n.markRx()
 			switch typ := icnLE.Uint16(buf[4:]); {
@@ -403,6 +400,10 @@ func (n *icomNet) civPump() {
 				n.dead.Store(true) // make Alive() fail now → prompt clean reconnect
 				debugLog.Printf("icom net: rig sent DISCONNECT on CI-V stream — session dropped by the rig")
 			case typ == 0x00 && k > 0x15 && buf[0x10] == 0xc1: // CI-V data
+				if quietSaid {
+					debugLog.Printf("icom net: CI-V replies are back after %s", time.Since(lastData).Round(time.Second))
+					quietSaid, gaveUp = false, false
+				}
 				lastData = time.Now()
 				n.trackRxSeq(icnLE.Uint16(buf[6:])) // note gaps for retransmit
 				civBytes := buf[0x15:k]
@@ -461,6 +462,15 @@ func (n *icomNet) civPump() {
 			_, _ = n.civ.Write(ocPkt)
 			debugLog.Printf("icom net: re-sent the CI-V open on the existing stream")
 		}
+		// The reopen was given five seconds. On a real IC-7760 it never works —
+		// the rig ignores it and only a fresh session brings CI-V back — so
+		// rather than sit out the 30 s watchdog, fail the link NOW and let the
+		// manager rebuild it: the outage drops from ~35 s to ~15.
+		if quietSaid && !gaveUp && time.Since(lastData) > 15*time.Second {
+			gaveUp = true
+			n.dead.Store(true)
+			debugLog.Printf("icom net: the reopen did not bring CI-V back — forcing a fresh session")
+		}
 		if time.Since(lastIdle) > 150*time.Millisecond {
 			_, _ = n.civ.Write(icnCtrl(0x00, 0, n.vID, n.vRemote))
 			lastIdle = time.Now()