feat(send): implement message edits

EditMessageText and EditMessageCaption edit via the sender's Edit builder
(parse mode, web-preview and markup options apply). EditMessageReplyMarkup goes
straight to messages.editMessage with only the markup set, so text and media
are left untouched; a nil markup removes the keyboard.

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

Author: ernado

edit.go

@@ -0,0 +1,72 @@
+package botapi
+
+import (
+	"context"
+
+	"github.com/gotd/td/tg"
+)
+
+// editText is the shared path for editing a message's text or caption.
+func (b *Bot) editText(ctx context.Context, chat ChatID, messageID int, text string, opts ...SendOption) (*Message, error) {
+	var cfg sendConfig
+	for _, o := range opts {
+		o(&cfg)
+	}
+
+	peer, err := b.resolveInputPeer(ctx, chat)
+	if err != nil {
+		return nil, err
+	}
+
+	styled, err := styledText(text, cfg.parseMode, b.peers.UserResolveHook(ctx))
+	if err != nil {
+		return nil, err
+	}
+
+	builder := &b.sender.To(peer).Builder
+	if cfg.disableWebPreview {
+		builder = builder.NoWebpage()
+	}
+	if cfg.markup != nil {
+		mkp, err := replyMarkupToTg(cfg.markup)
+		if err != nil {
+			return nil, err
+		}
+		builder = builder.Markup(mkp)
+	}
+
+	resp, err := builder.Edit(messageID).StyledText(ctx, styled...)
+	return b.sentMessage(ctx, peer, resp, err)
+}
+
+// EditMessageText edits the text of a message and returns the edited message.
+func (b *Bot) EditMessageText(ctx context.Context, chat ChatID, messageID int, text string, opts ...SendOption) (*Message, error) {
+	return b.editText(ctx, chat, messageID, text, opts...)
+}
+
+// EditMessageCaption edits the caption of a media message and returns the
+// edited message.
+func (b *Bot) EditMessageCaption(ctx context.Context, chat ChatID, messageID int, caption string, opts ...SendOption) (*Message, error) {
+	return b.editText(ctx, chat, messageID, caption, opts...)
+}
+
+// EditMessageReplyMarkup edits only the reply markup of a message, leaving its
+// text and media unchanged. A nil markup removes the keyboard.
+func (b *Bot) EditMessageReplyMarkup(ctx context.Context, chat ChatID, messageID int, markup ReplyMarkup) (*Message, error) {
+	peer, err := b.resolveInputPeer(ctx, chat)
+	if err != nil {
+		return nil, err
+	}
+
+	req := &tg.MessagesEditMessageRequest{Peer: peer, ID: messageID}
+	if markup != nil {
+		mkp, err := replyMarkupToTg(markup)
+		if err != nil {
+			return nil, err
+		}
+		req.SetReplyMarkup(mkp)
+	}
+
+	resp, err := b.raw.MessagesEditMessage(ctx, req)
+	return b.sentMessage(ctx, peer, resp, err)
+}