fix: only answer unknown /commands, not ordinary messages

The default handler fired for every update the command matchers didn't
claim, so plain chatter, service messages, media, and replies to the bot
all drew a "Nieznana komenda" response — spammy in group chats. Gate the
fallback on a leading bot_command entity so only real (unrecognized)
commands get the help reply.

telegram.go

@@ -156,14 +156,29 @@ func (h *botHandlers) sync(ctx context.Context, b *bot.Bot, update *models.Updat
 		"Zsynchronizowano: %d tygodni, %d osób.", len(rota.Weeks), len(rota.People)))
 }
 
-// unknown is the fallback for any text the bot does not recognize.
+// unknown is the fallback for any update the command matchers don't claim. It
+// only answers messages that actually carry a bot_command entity (a mistyped or
+// unsupported /command); plain chatter, service messages (joins/pins), media,
+// and replies to the bot fall through here too but get no response, so the bot
+// stays quiet in groups instead of "Nieznana komenda"-spamming every message.
 func (h *botHandlers) unknown(ctx context.Context, b *bot.Bot, update *models.Update) {
-	if update.Message == nil {
+	if update.Message == nil || !hasCommandEntity(update.Message.Entities) {
 		return
 	}
 	h.reply(ctx, b, update, "Nieznana komenda. Użyj /kto_sprzata lub /sync.")
 }
 
+// hasCommandEntity reports whether the message carries any bot_command entity,
+// i.e. the user typed a /command (recognized or not) rather than plain text.
+func hasCommandEntity(entities []models.MessageEntity) bool {
+	for _, e := range entities {
+		if e.Type == models.MessageEntityTypeBotCommand {
+			return true
+		}
+	}
+	return false
+}
+
 // reply sends text back to the originating chat, logging send failures.
 func (h *botHandlers) reply(ctx context.Context, b *bot.Bot, update *models.Update, text string) {
 	if update.Message == nil {

telegram_test.go

@@ -293,18 +293,39 @@ func TestSyncReplyFailure(t *testing.T) {
 	}
 }
 
-// TestUnknownReply checks the fallback handler answers unrecognized text.
+// TestUnknownReply checks the fallback answers an unrecognized /command (a
+// message carrying a bot_command entity that no matcher claimed).
 func TestUnknownReply(t *testing.T) {
 	svc := testService(t, Rota{}, nil)
 	b, sent := newTestBot(t)
 	h := &botHandlers{svc: svc, now: fixedNow()}
 
+	cmd := &models.Update{Message: &models.Message{
+		Text:     "/foo",
+		Chat:     models.Chat{ID: 123},
+		Entities: cmdEntity("/foo"),
+	}}
+	h.unknown(context.Background(), b, cmd)
+
+	got := sent()
+	want := "Nieznana komenda. Użyj /kto_sprzata lub /sync."
+	if len(got) != 1 || got[0] != want {
+		t.Fatalf("reply = %v, want [%q]", got, want)
+	}
+}
+
+// TestUnknownPlainTextIgnored checks ordinary chatter (no bot_command entity)
+// gets no reply, so the bot doesn't spam "Nieznana komenda" on every group
+// message, service notice, or reply to its own messages.
+func TestUnknownPlainTextIgnored(t *testing.T) {
+	svc := testService(t, Rota{}, nil)
+	b, sent := newTestBot(t)
+	h := &botHandlers{svc: svc, now: fixedNow()}
+
 	h.unknown(context.Background(), b, updateMsg(123, "siema"))
 
-	got := sent()
-	want := "Nieznana komenda. Użyj /kto_sprzata lub /sync."
-	if len(got) != 1 || got[0] != want {
-		t.Fatalf("reply = %v, want [%q]", got, want)
+	if got := sent(); len(got) != 0 {
+		t.Fatalf("plain text should not reply, got %v", got)
 	}
 }