fix(hamlog): stop offering an upload that cannot succeed

HAMLOG.online no longer issues API keys, and its upload API takes
nothing else. An operator without a key cannot obtain one, so the
auto-upload switch, the on-close sweep and the 'Send to' entry were all
arming something that could only fail — silently, once per QSO.

Closed at the source rather than hidden in the UI: the upload returns a
sentinel that says why, the manager stops routing to it and says so once
a session, and the manual path refuses with the same words. The settings
page states it plainly instead of showing a switch that does nothing.

Nothing else goes. Their confirmations arrive as an ADIF FILE and never
needed a key, so that import stays; the sent/received state already in
operators' logs stays readable, filterable and bulk-editable; and the
upload itself is kept whole as uploadHamlogLive, still covered by its
request-shape tests, against the day keys come back.

internal/extsvc/manager.go

@@ -84,9 +84,10 @@ type Deps struct {
 type Manager struct {
 	deps Deps
 
-	mu  sync.Mutex
-	cfg ExternalServices
-	rnd *rand.Rand
+	mu               sync.Mutex
+	cfg              ExternalServices
+	rnd              *rand.Rand
+	hamlogClosedOnce sync.Once
 }
 
 // maxUploadAttempts bounds retries of a transient upload failure.
@@ -230,13 +231,13 @@ func (m *Manager) OnQSOLogged(id int64) {
 			m.route(ServiceCloudlog, id, c)
 		}
 	}
-	// HAMLOG.online — one API key and nothing else to get wrong.
-	if h := cfg.Hamlog; h.AutoUpload {
-		if h.APIKey == "" {
-			m.logf("extsvc: hamlog auto-upload is ON but no API key is set (QSO %d not sent)", id)
-		} else {
-			m.route(ServiceHamlog, id, h)
-		}
+	// HAMLOG.online is closed to uploads — see ErrHamlogClosed. Said once per
+	// session rather than per QSO, because an operator who left the switch on
+	// deserves to know why nothing leaves, and does not deserve it every minute.
+	if cfg.Hamlog.AutoUpload {
+		m.hamlogClosedOnce.Do(func() {
+			m.logf("extsvc: %v", ErrHamlogClosed)
+		})
 	}
 	// HamQTH — the callbook credentials double as the logbook login.
 	if h := cfg.HamQTH; h.AutoUpload {
@@ -296,9 +297,7 @@ func (m *Manager) onCloseServices() []Service {
 	if c := cfg.Cloudlog; c.AutoUpload && c.UploadMode == ModeOnClose && c.URL != "" && c.APIKey != "" && c.StationID != "" {
 		out = append(out, ServiceCloudlog)
 	}
-	if h := cfg.Hamlog; h.AutoUpload && h.UploadMode == ModeOnClose && h.APIKey != "" {
-		out = append(out, ServiceHamlog)
-	}
+
 	if h := cfg.HamQTH; h.AutoUpload && h.UploadMode == ModeOnClose && h.Username != "" && h.Password != "" {
 		out = append(out, ServiceHamQTH)
 	}
@@ -348,8 +347,7 @@ func (m *Manager) FlushOnClose() int {
 			uploaded += m.flushOneByOne(svc, ids, cfg.HRDLog)
 		case ServiceCloudlog:
 			uploaded += m.flushOneByOne(svc, ids, cfg.Cloudlog)
-		case ServiceHamlog:
-			uploaded += m.flushOneByOne(svc, ids, cfg.Hamlog)
+
 		case ServiceHamQTH:
 			uploaded += m.flushOneByOne(svc, ids, cfg.HamQTH)
 		}