fix(telegram): support card — text_mention name, no command/dead link

The topic info card built the profile link as `tg://user?id=`, which
clients render as dead text for a user they don't already know (the
test-vs-prod difference an operator saw), and it put the raw display
name through HTML — so a name starting with "/" was auto-detected as a
tappable bot command that fired when tapped.

Render the card with message entities instead: the display name is
covered by a `text_mention` entity (the reliable way to mention a
username-less user the bot has already seen — it messaged the bot),
which links the profile AND, because the name sits inside an entity,
suppresses the "/command" and "@mention" auto-detection on it. Drop the
HTML parse mode and the tg:// link. Entity offsets are UTF-16.

docs/ARCHITECTURE.md

@@ -1204,8 +1204,10 @@ migration.
 **Telegram support relay.** Separate from the in-app Feedback above, the bot offers a direct
 support channel for users who message it on Telegram. Any message other than `/start` is relayed
 into a private **forum supergroup** (`TELEGRAM_SUPPORT_CHAT_ID`): a user's first message opens a
-dedicated **forum topic** whose first message is an info card (name, @username, language, premium,
-id, profile deep-link) carrying a Block/Unblock toggle and a Clear button; every message is then
+dedicated **forum topic** whose first message is an info card (the name is a tappable profile
+mention via a `text_mention` entity — which also keeps a name beginning with `/` from being read as
+a command — plus @username, language, premium, id) carrying a Block/Unblock toggle and a Clear
+button; every message is then
 copied into that topic (`copyMessage`, so any content — text, media, voice, files — carries over).
 Any **administrator** of the support chat who writes in a user's topic has their message copied
 back to that user; non-admins and the bot's own posts are ignored (the loop guard). Block drops the

platform/telegram/README.md

@@ -65,8 +65,9 @@ Telegram identity to an account from a browser. Both map a rejection to gRPC
   `chat_member` updates, which Telegram delivers only to a chat admin.
 - **Support relay (optional).** When `TELEGRAM_SUPPORT_CHAT_ID` names a private **forum
   supergroup**, the bot runs a direct support channel for users who message it. A user's first
-  non-`/start` message opens a dedicated **forum topic** whose first message is an info card (name,
-  @username, language, premium, id, `tg://user` profile link) carrying a **Block/Unblock** toggle
+  non-`/start` message opens a dedicated **forum topic** whose first message is an info card (the
+  name is a tappable profile mention via a `text_mention` entity — which also stops a name starting
+  with `/` from rendering as a command — plus @username, language, premium, id) with a **Block/Unblock** toggle
   and a **Clear** button; each message is then copied into that topic (`copyMessage`, so any content
   — text, media, voice, files — carries over). Any **administrator** of the support chat who writes
   in a user's topic has it copied back to that user; the bot's own posts and non-admins are ignored

platform/telegram/internal/bot/support.go

@@ -3,11 +3,11 @@ package bot
 import (
 	"context"
 	"fmt"
-	"html"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
+	"unicode/utf16"
 
 	tgbot "github.com/go-telegram/bot"
 	"github.com/go-telegram/bot/models"
@@ -270,11 +270,12 @@ func (t *Bot) openSupportTopic(ctx context.Context, u *models.User) (int, error)
 		return 0, fmt.Errorf("create forum topic: %w", err)
 	}
 	headerID := 0
+	cardText, cardEntities := supportCard(u)
 	header, err := t.api.SendMessage(ctx, &tgbot.SendMessageParams{
 		ChatID:          t.supportChatID,
 		MessageThreadID: topic.MessageThreadID,
-		Text:            supportCardText(u),
-		ParseMode:       models.ParseModeHTML,
+		Text:            cardText,
+		Entities:        cardEntities,
 		ReplyMarkup:     supportCardMarkup(u.ID, false),
 	})
 	if err != nil {
@@ -396,16 +397,22 @@ func supportTopicName(u *models.User) string {
 	return name
 }
 
-// supportCardText renders the info card describing the user. User-controlled fields
-// are HTML-escaped because the card uses HTML parse mode for the profile link.
-func supportCardText(u *models.User) string {
-	name := html.EscapeString(strings.TrimSpace(u.FirstName + " " + u.LastName))
+// supportCard renders the topic info card describing the user and the message
+// entities for it. The display name is covered by a text_mention entity: it links to
+// the user's profile (the reliable way to mention a user who has no public username —
+// the bot has seen them, since they messaged it) and, because the name sits inside an
+// entity, Telegram does not auto-detect a leading "/" as a bot command or a stray
+// "@handle" inside the name as a mention. The remaining lines are plain text; a public
+// @username, when present, is left for Telegram to auto-link. Entity offsets are in
+// UTF-16 code units, as the Bot API requires; the name is at offset 0.
+func supportCard(u *models.User) (string, []models.MessageEntity) {
+	name := strings.TrimSpace(u.FirstName + " " + u.LastName)
 	if name == "" {
-		name = "—"
+		name = "user " + strconv.FormatInt(u.ID, 10)
 	}
 	username := "—"
 	if u.Username != "" {
-		username = "@" + html.EscapeString(u.Username)
+		username = "@" + u.Username
 	}
 	lang := u.LanguageCode
 	if lang == "" {
@@ -416,12 +423,17 @@ func supportCardText(u *models.User) string {
 		premium = "да"
 	}
 	var b strings.Builder
-	fmt.Fprintf(&b, "<b>%s</b>\n", name)
-	fmt.Fprintf(&b, "Username: %s\n", username)
-	fmt.Fprintf(&b, "ID: <code>%d</code>\n", u.ID)
-	fmt.Fprintf(&b, "Язык: %s · Premium: %s\n", html.EscapeString(lang), premium)
-	fmt.Fprintf(&b, `<a href="tg://user?id=%d">Открыть профиль</a>`, u.ID)
-	return b.String()
+	b.WriteString(name)
+	fmt.Fprintf(&b, "\nUsername: %s", username)
+	fmt.Fprintf(&b, "\nID: %d", u.ID)
+	fmt.Fprintf(&b, "\nЯзык: %s · Premium: %s", lang, premium)
+	entities := []models.MessageEntity{{
+		Type:   models.MessageEntityTypeTextMention,
+		Offset: 0,
+		Length: len(utf16.Encode([]rune(name))),
+		User:   &models.User{ID: u.ID},
+	}}
+	return b.String(), entities
 }
 
 // isTopicMissingErr reports whether err is Telegram's deleted/absent forum-topic

platform/telegram/internal/bot/support_test.go

@@ -360,21 +360,53 @@ func TestParseSupportCallback(t *testing.T) {
 	}
 }
 
-func TestSupportCardTextEscapes(t *testing.T) {
-	u := &models.User{ID: 7, FirstName: "<b>Ann</b>", Username: "ann", LanguageCode: "ru", IsPremium: true}
-	card := supportCardText(u)
-	if strings.Contains(card, "<b>Ann</b>") {
-		t.Error("user-supplied first name was not HTML-escaped in the card")
+func TestSupportCard(t *testing.T) {
+	t.Run("name is a plain-text mention, not a command", func(t *testing.T) {
+		u := &models.User{ID: 7, FirstName: "/start", Username: "ann", LanguageCode: "ru", IsPremium: true}
+		text, ents := supportCard(u)
+		// The name is rendered verbatim (no HTML, no escaping) at the start of the card.
+		if !strings.HasPrefix(text, "/start\n") {
+			t.Errorf("card = %q, want it to start with the raw name", text)
 		}
-	if !strings.Contains(card, "&lt;b&gt;Ann&lt;/b&gt;") {
-		t.Errorf("card = %q, want the escaped name", card)
+		// A text_mention entity covers exactly the name with the user id — this both
+		// suppresses the "/start" command auto-detection and links the profile.
+		if len(ents) != 1 {
+			t.Fatalf("entities = %d, want 1", len(ents))
 		}
-	if !strings.Contains(card, "tg://user?id=7") {
-		t.Error("card missing the profile deep link")
+		e := ents[0]
+		if e.Type != models.MessageEntityTypeTextMention || e.Offset != 0 || e.Length != len("/start") {
+			t.Errorf("entity = %+v, want a text_mention over the name", e)
 		}
-	if !strings.Contains(card, "Premium: да") {
-		t.Error("card missing the premium flag")
+		if e.User == nil || e.User.ID != 7 {
+			t.Errorf("entity user = %+v, want id 7", e.User)
 		}
+		if strings.Contains(text, "tg://") || strings.Contains(text, "<") {
+			t.Errorf("card = %q, want no tg:// link and no HTML", text)
+		}
+		if !strings.Contains(text, "Premium: да") || !strings.Contains(text, "@ann") {
+			t.Errorf("card = %q, want premium + @username", text)
+		}
+	})
+
+	t.Run("entity length is UTF-16, not runes", func(t *testing.T) {
+		// "😀A" is 2 runes but 3 UTF-16 code units (the emoji is a surrogate pair).
+		u := &models.User{ID: 9, FirstName: "😀A"}
+		_, ents := supportCard(u)
+		if len(ents) != 1 || ents[0].Length != 3 {
+			t.Fatalf("entity = %+v, want length 3 UTF-16 units", ents)
+		}
+	})
+
+	t.Run("nameless user falls back to an id label", func(t *testing.T) {
+		u := &models.User{ID: 42}
+		text, ents := supportCard(u)
+		if !strings.HasPrefix(text, "user 42") {
+			t.Errorf("card = %q, want the id fallback name", text)
+		}
+		if ents[0].Length != len("user 42") {
+			t.Errorf("entity length = %d, want it over the fallback name", ents[0].Length)
+		}
+	})
 }
 
 func TestSupportTopicName(t *testing.T) {