feat(channels): make Channel.Send return delivered message IDs (#2190)

* feat(channels): Channel.Send and MediaSender.SendMedia return delivered message IDs

Change Channel.Send signature from (ctx, msg) error to (ctx, msg) ([]string, error)
and MediaSender.SendMedia similarly, so callers can capture platform message IDs
for threading, reactions, and history annotation.

Adapters that return real IDs: Telegram (per-chunk MessageID), Discord (Message.ID),
Slack Send (ts), QQ (sentMsg.ID), Matrix (EventID). Slack SendMedia returns nil
because UploadFileV2 does not expose the posted message timestamp in its response.
All other adapters return nil IDs.

preSend and sendWithRetry in manager.go updated to propagate ([]string, bool).
README examples updated for both English and Chinese docs.

* style: apply golangci-lint fixes (golines)

* docs: fix Send migration guide — restore old error-only signature in before/after example

pkg/channels/feishu/feishu_32.go

@@ -36,8 +36,8 @@ func (c *FeishuChannel) Stop(ctx context.Context) error {
 }
 
 // Send is a stub method to satisfy the Channel interface
-func (c *FeishuChannel) Send(ctx context.Context, msg bus.OutboundMessage) error {
-	return errUnsupported
+func (c *FeishuChannel) Send(ctx context.Context, msg bus.OutboundMessage) ([]string, error) {
+	return nil, errUnsupported
 }
 
 // EditMessage is a stub method to satisfy MessageEditor
@@ -56,6 +56,6 @@ func (c *FeishuChannel) ReactToMessage(ctx context.Context, chatID, messageID st
 }
 
 // SendMedia is a stub method to satisfy MediaSender
-func (c *FeishuChannel) SendMedia(ctx context.Context, msg bus.OutboundMediaMessage) error {
-	return errUnsupported
+func (c *FeishuChannel) SendMedia(ctx context.Context, msg bus.OutboundMediaMessage) ([]string, error) {
+	return nil, errUnsupported
 }

pkg/channels/feishu/feishu_64.go

@@ -131,26 +131,26 @@ func (c *FeishuChannel) Stop(ctx context.Context) error {
 
 // Send sends a message using Interactive Card format for markdown rendering.
 // Falls back to plain text message if card sending fails (e.g., table limit exceeded).
-func (c *FeishuChannel) Send(ctx context.Context, msg bus.OutboundMessage) error {
+func (c *FeishuChannel) Send(ctx context.Context, msg bus.OutboundMessage) ([]string, error) {
 	if !c.IsRunning() {
-		return channels.ErrNotRunning
+		return nil, channels.ErrNotRunning
 	}
 
 	if msg.ChatID == "" {
-		return fmt.Errorf("chat ID is empty: %w", channels.ErrSendFailed)
+		return nil, fmt.Errorf("chat ID is empty: %w", channels.ErrSendFailed)
 	}
 
 	// Build interactive card with markdown content
 	cardContent, err := buildMarkdownCard(msg.Content)
 	if err != nil {
 		// If card build fails, fall back to plain text
-		return c.sendText(ctx, msg.ChatID, msg.Content)
+		return nil, c.sendText(ctx, msg.ChatID, msg.Content)
 	}
 
 	// First attempt: try sending as interactive card
 	err = c.sendCard(ctx, msg.ChatID, cardContent)
 	if err == nil {
-		return nil
+		return nil, nil
 	}
 
 	// Check if error is due to card table limit (error code 11310)
@@ -167,14 +167,14 @@ func (c *FeishuChannel) Send(ctx context.Context, msg bus.OutboundMessage) error
 		// Second attempt: fall back to plain text message
 		textErr := c.sendText(ctx, msg.ChatID, msg.Content)
 		if textErr == nil {
-			return nil
+			return nil, nil
 		}
 		// If text also fails, return the text error
-		return textErr
+		return nil, textErr
 	}
 
 	// For other errors, return the original card error
-	return err
+	return nil, err
 }
 
 // EditMessage implements channels.MessageEditor.
@@ -310,27 +310,27 @@ func (c *FeishuChannel) ReactToMessage(ctx context.Context, chatID, messageID st
 
 // SendMedia implements channels.MediaSender.
 // Uploads images/files via Feishu API then sends as messages.
-func (c *FeishuChannel) SendMedia(ctx context.Context, msg bus.OutboundMediaMessage) error {
+func (c *FeishuChannel) SendMedia(ctx context.Context, msg bus.OutboundMediaMessage) ([]string, error) {
 	if !c.IsRunning() {
-		return channels.ErrNotRunning
+		return nil, channels.ErrNotRunning
 	}
 
 	if msg.ChatID == "" {
-		return fmt.Errorf("chat ID is empty: %w", channels.ErrSendFailed)
+		return nil, fmt.Errorf("chat ID is empty: %w", channels.ErrSendFailed)
 	}
 
 	store := c.GetMediaStore()
 	if store == nil {
-		return fmt.Errorf("no media store available: %w", channels.ErrSendFailed)
+		return nil, fmt.Errorf("no media store available: %w", channels.ErrSendFailed)
 	}
 
 	for _, part := range msg.Parts {
 		if err := c.sendMediaPart(ctx, msg.ChatID, part, store); err != nil {
-			return err
+			return nil, err
 		}
 	}
 
-	return nil
+	return nil, nil
 }
 
 // sendMediaPart resolves and sends a single media part.