feat(send): implement ForwardMessage and DeleteMessage(s)

ForwardMessage forwards by id between resolved peers (Silent/ProtectContent
apply) and returns the forwarded message. DeleteMessage/DeleteMessages revoke
messages for everyone via the sender's Revoke builder, which is peer-aware
(handles channels).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ernado

forward_delete.go

@@ -0,0 +1,48 @@
+package botapi
+
+import "context"
+
+// ForwardMessage forwards a single message from one chat to another and returns
+// the forwarded message. Silent and ProtectContent options apply.
+func (b *Bot) ForwardMessage(ctx context.Context, to, from ChatID, messageID int, opts ...SendOption) (*Message, error) {
+	var cfg sendConfig
+	for _, o := range opts {
+		o(&cfg)
+	}
+
+	toPeer, err := b.resolveInputPeer(ctx, to)
+	if err != nil {
+		return nil, err
+	}
+	fromPeer, err := b.resolveInputPeer(ctx, from)
+	if err != nil {
+		return nil, err
+	}
+
+	builder := &b.sender.To(toPeer).Builder
+	builder, err = b.applySendConfig(builder, cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := builder.ForwardIDs(fromPeer, messageID).Send(ctx)
+	return b.sentMessage(ctx, toPeer, resp, err)
+}
+
+// DeleteMessage deletes a message for everyone in the chat.
+func (b *Bot) DeleteMessage(ctx context.Context, chat ChatID, messageID int) error {
+	return b.DeleteMessages(ctx, chat, []int{messageID})
+}
+
+// DeleteMessages deletes several messages for everyone in the chat.
+func (b *Bot) DeleteMessages(ctx context.Context, chat ChatID, messageIDs []int) error {
+	if len(messageIDs) == 0 {
+		return nil
+	}
+	peer, err := b.resolveInputPeer(ctx, chat)
+	if err != nil {
+		return err
+	}
+	_, err = b.sender.To(peer).Revoke().Messages(ctx, messageIDs...)
+	return asAPIError(err)
+}