fix(telegram): clear draft after materializing DM stream

When using draft_transport in Telegram DMs, the preview draft sometimes
stays in the input area after the real message is delivered, showing a
brief duplicate reply.

Clear the stale draft by sending an empty sendMessageDraft as soon as
the final message is sent in Send(). The cleanup is asynchronous and
best-effort so it won't block message delivery.

Co-authored-by: Badgerbees <rapabelias@gmail.com>

internal/channels/telegram/channel.go

@@ -46,6 +46,7 @@ type Channel struct {
 	pollDone         chan struct{}       // closed when polling goroutine exits
 	handlerWg        sync.WaitGroup     // tracks in-flight handler goroutines for graceful shutdown
 	handlerSem       chan struct{}       // bounded semaphore for concurrent handler goroutines
+	pendingDraftID   sync.Map           // localKey string → int (draftID)
 }
 
 type thinkingCancel struct {

internal/channels/telegram/send.go

@@ -161,6 +161,24 @@ func (c *Channel) Send(ctx context.Context, msg bus.OutboundMessage) error {
 		}
 	}
 
+	// Captured draft cleanup: if this message follows a DM stream that used the
+	// draft transport, we must clear the stale draft as soon as this bubble is sent.
+	if pID, ok := c.pendingDraftID.LoadAndDelete(localKey); ok {
+		draftID := pID.(int)
+		go func() {
+			params := &telego.SendMessageDraftParams{
+				ChatID:          chatID,
+				DraftID:         draftID,
+				Text:            "",
+				MessageThreadID: resolveThreadIDForSend(threadID),
+			}
+			// Best-effort with Background ctx — caller ctx may already be cancelled.
+			if err := c.bot.SendMessageDraft(context.Background(), params); err != nil {
+				slog.Debug("telegram: draft clear failed (cosmetic)", "chat_id", chatID, "draft_id", draftID, "error", err)
+			}
+		}()
+	}
+
 	// Placeholder update (e.g. LLM retry notification): edit the placeholder
 	// but keep it alive for the final response. Don't stop typing or cleanup.
 	if msg.Metadata["placeholder_update"] == "true" {

internal/channels/telegram/stream.go

@@ -331,6 +331,11 @@ func (c *Channel) FinalizeStream(ctx context.Context, chatID string, stream chan
 		slog.Warn("stream: initial send landed but ID unknown. Suppressing fallback message to avoid duplicate.", "chat_id", chatID)
 	}
 
+	// Capture draft ID for clearing after the final Send()
+	if ds, ok := stream.(*DraftStream); ok && ds.UsedDraftTransport() {
+		c.pendingDraftID.Store(chatID, ds.draftID)
+	}
+
 	// Stop thinking animation
 	if stop, ok := c.stopThinking.Load(chatID); ok {
 		if cf, ok := stop.(*thinkingCancel); ok {