fix(lotw): count out the wait before the first byte

The progress lines only start once bytes arrive, and on a large account nothing
arrives for minutes — LoTW builds the entire report before sending any of it.
That silence WAS the complaint: the window still just said 'working'.

A heartbeat every fifteen seconds until the headers land, then the HTTP status,
then the megabytes — the first at 256 KB rather than 1 MB, so the very first
sign that it is moving comes early.

internal/extsvc/lotw.go

@@ -50,7 +50,7 @@ func readWithProgress(ctx context.Context, r io.Reader, note func(string)) ([]by
 		total int64
 		last  = time.Now()
 		buf   = make([]byte, 64*1024)
-		next  = int64(1024 * 1024) // first report at 1 MB
+		next  = int64(256 * 1024) // first report early — proof it is moving
 	)
 	for {
 		if err := ctx.Err(); err != nil {
@@ -63,7 +63,7 @@ func readWithProgress(ctx context.Context, r io.Reader, note func(string)) ([]by
 			last = time.Now()
 			if total >= next {
 				say(note, fmt.Sprintf("  … %.1f MB received", float64(total)/(1024*1024)))
-				next = total + 1024*1024
+				next = total + 512*1024
 			}
 			if total >= lotwMaxBytes {
 				return out, nil
@@ -142,6 +142,28 @@ func DownloadLoTWConfirmations(ctx context.Context, client *http.Client, cfg Ser
 	// again. Three tries, spaced, and each one said out loud: an operator whose
 	// download takes four minutes because the ARRL is loaded should be able to
 	// see that rather than guess it.
+	// LoTW sends nothing at all until the whole report is built — minutes for a
+	// large account. That silence was the entire complaint: a window saying
+	// "working" with no way to tell a busy server from a dead one. Count it out
+	// loud until the first byte.
+	beat := make(chan struct{})
+	go func() {
+		start := time.Now()
+		tick := time.NewTicker(15 * time.Second)
+		defer tick.Stop()
+		for {
+			select {
+			case <-beat:
+				return
+			case <-ctx.Done():
+				return
+			case <-tick.C:
+				say(note, fmt.Sprintf("  … still waiting for LoTW to build the report (%.0f s)", time.Since(start).Seconds()))
+			}
+		}
+	}()
+	defer close(beat)
+
 	var resp *http.Response
 	for attempt := 1; ; attempt++ {
 		resp, err = client.Do(req) //nolint:bodyclose // closed below or in the retry
@@ -170,6 +192,7 @@ func DownloadLoTWConfirmations(ctx context.Context, client *http.Client, cfg Ser
 		return "", fmt.Errorf("lotw: request failed: %w", err)
 	}
 	defer resp.Body.Close()
+	say(note, fmt.Sprintf("LoTW answered (HTTP %d) — receiving…", resp.StatusCode))
 	body, err := readWithProgress(ctx, resp.Body, note)
 	if err != nil {
 		return "", fmt.Errorf("lotw: read response: %w", err)