fix(telegram): omit nil reply markup from JSON

backend/internal/telegram/client.go

@@ -15,7 +15,8 @@ import (
 type Client struct { Token string; ChatIDs []string; HTTPClient *http.Client }
 func NewClient(token string, chatIDs []string) *Client { clean:=make([]string,0,len(chatIDs)); for _,id:=range chatIDs { if id=strings.TrimSpace(id); id!="" { clean=append(clean,id) } }; return &Client{Token:strings.TrimSpace(token),ChatIDs:clean,HTTPClient:&http.Client{Timeout:30*time.Second}} }
 func (c *Client) Enabled() bool { return c!=nil && c.Token!="" && len(c.ChatIDs)>0 }
-type sendMessageRequest struct { ChatID string `json:"chat_id"`; Text string `json:"text"`; ParseMode string `json:"parse_mode,omitempty"`; ReplyMarkup interface{} `json:"reply_markup,omitempty"` }
+
+type sendMessageRequest struct { ChatID string `json:"chat_id"`; Text string `json:"text"`; ParseMode string `json:"parse_mode,omitempty"`; ReplyMarkup *InlineKeyboardMarkup `json:"reply_markup,omitempty"` }
 type telegramResponse struct { OK bool `json:"ok"`; Description string `json:"description"` }
 type InlineKeyboardMarkup struct { InlineKeyboard [][]InlineButton `json:"inline_keyboard"` }
 type InlineButton struct { Text string `json:"text"`; CallbackData string `json:"callback_data,omitempty"`; URL string `json:"url,omitempty"` }
@@ -29,6 +30,4 @@ func (c *Client) Validate() error { if c==nil||c.Token=="" {return fmt.Errorf("t
 func (c *Client) sendOne(chatID,text string,markup *InlineKeyboardMarkup) error { body,err:=json.Marshal(sendMessageRequest{ChatID:chatID,Text:text,ParseMode:"HTML",ReplyMarkup:markup});if err!=nil{return err};return c.post(fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage",c.Token),body) }
 func (c *Client) post(endpoint string,body []byte) error { req,err:=http.NewRequest(http.MethodPost,endpoint,bytes.NewReader(body));if err!=nil{return err};req.Header.Set("Content-Type","application/json");resp,err:=c.HTTPClient.Do(req);if err!=nil{return err};defer resp.Body.Close();raw,_:=io.ReadAll(io.LimitReader(resp.Body,4096));var parsed telegramResponse;if err:=json.Unmarshal(raw,&parsed);err!=nil{return fmt.Errorf("telegram API returned invalid response: %w",err)};if resp.StatusCode>=300||!parsed.OK{return fmt.Errorf("telegram API %d: %s",resp.StatusCode,parsed.Description)};return nil }
 
-// splitTelegramHTML keeps simple Telegram HTML tags intact and prefers newline
-// boundaries. It also reopens active tags in the next chunk.
-func splitTelegramHTML(text string, max int) []string { if utf8.RuneCountInString(text)<=max{return []string{text}};var chunks []string;var buf strings.Builder;var stack []string;visible:=0;flush:=func(){if buf.Len()==0{return};s:=buf.String();for i:=len(stack)-1;i>=0;i--{s+="</"+stack[i]+">"};chunks=append(chunks,s);buf.Reset();visible=0;for _,tag:=range stack{buf.WriteString("<"+tag+">")}};for i:=0;i<len(text);{if text[i]=='<' {j:=strings.IndexByte(text[i:],'>');if j<0 {break};j+=i+1;tagRaw:=text[i+1:j-1];lower:=strings.ToLower(strings.TrimSpace(tagRaw));buf.WriteString(text[i:j]);if strings.HasPrefix(lower,"/"){name:=strings.TrimSpace(strings.TrimPrefix(lower,"/"));for k:=len(stack)-1;k>=0;k--{if stack[k]==name{stack=append(stack[:k],stack[k+1:]...);break}}} else if lower=="b"||lower=="strong"||lower=="i"||lower=="em"||lower=="u"||lower=="s"||lower=="code"||lower=="pre" {stack=append(stack,lower)};i=j;continue};r,n:=utf8.DecodeRuneInString(text[i:]);if visible+1>max-64 {flush();continue};buf.WriteRune(r);visible++;i+=n;if r=='\n'&&visible>max/2 { } };if buf.Len()>0 {s:=buf.String();for i:=len(stack)-1;i>=0;i--{s+="</"+stack[i]+">"};chunks=append(chunks,s)};return chunks }
+func splitTelegramHTML(text string, max int) []string { if utf8.RuneCountInString(text)<=max{return []string{text}};var chunks []string;var buf strings.Builder;var stack []string;visible:=0;flush:=func(){if buf.Len()==0{return};s:=buf.String();for i:=len(stack)-1;i>=0;i--{s+="</"+stack[i]+">"};chunks=append(chunks,s);buf.Reset();visible=0;for _,tag:=range stack{buf.WriteString("<"+tag+">")}};for i:=0;i<len(text);{if text[i]=='<' {j:=strings.IndexByte(text[i:],'>');if j<0 {break};j+=i+1;tagRaw:=text[i+1:j-1];lower:=strings.ToLower(strings.TrimSpace(tagRaw));buf.WriteString(text[i:j]);if strings.HasPrefix(lower,"/"){name:=strings.TrimSpace(strings.TrimPrefix(lower,"/"));for k:=len(stack)-1;k>=0;k--{if stack[k]==name{stack=append(stack[:k],stack[k+1:]...);break}}} else if lower=="b"||lower=="strong"||lower=="i"||lower=="em"||lower=="u"||lower=="s"||lower=="code"||lower=="pre" {stack=append(stack,lower)};i=j;continue};r,n:=utf8.DecodeRuneInString(text[i:]);if visible+1>max-64 {flush();continue};buf.WriteRune(r);visible++;i+=n};if buf.Len()>0 {s:=buf.String();for i:=len(stack)-1;i>=0;i--{s+="</"+stack[i]+">"};chunks=append(chunks,s)};return chunks }