Interactive /mybots menu for @BotFather

Button-driven bot management: paginated picker, per-bot API token /
revoke, Edit Bot (name/description/about/commands/botpic), Bot Settings
toggles (inline/groups/privacy), and delete. Navigation edits the menu
message in place via a new editServiceBotMessage helper.

Edit Botpic accepts a photo the user sends to @BotFather and sets it as
the bot's profile photo (new files.SetAvatarFromExistingPhoto, wired
through bots.SetBotUserpic / WithBotAvatarStore); photos.uploadProfilePhoto
does not accept a bot target so this is the only route.

internal/app/files/bot_avatar.go

@@ -0,0 +1,78 @@
+package files
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"go.uber.org/zap"
+
+	"telesrv/internal/domain"
+)
+
+// maxBotAvatarSourceBytes bounds the source image @BotFather turns into a bot's
+// profile photo. A profile photo a user sends in a chat is a server-rendered
+// message-size JPEG, comfortably under this.
+const maxBotAvatarSourceBytes = 12 << 20
+
+// SetAvatarFromExistingPhoto renders an already-stored photo (typically one a
+// user just sent to a service bot) into the s/a/c avatar size set and makes it
+// the current profile photo of ownerType/ownerID.
+//
+// It is the path @BotFather's "Edit Botpic" uses: photos.uploadProfilePhoto#bot
+// is not accepted, and the source is a message photo rather than a fresh upload,
+// so the ordinary UploadProfilePhoto path does not apply.
+func (s *Service) SetAvatarFromExistingPhoto(ctx context.Context, ownerType domain.PeerType, ownerID, sourcePhotoID int64, date int) (domain.Photo, error) {
+	if ownerID <= 0 || sourcePhotoID <= 0 {
+		return domain.Photo{}, domain.ErrPhotoInvalid
+	}
+	source, found, err := s.media.GetPhoto(ctx, sourcePhotoID)
+	if err != nil {
+		return domain.Photo{}, err
+	}
+	if !found {
+		return domain.Photo{}, domain.ErrPhotoInvalid
+	}
+	data, ok := s.photoSourceBytes(ctx, source)
+	if !ok || !s.ValidateAvatarUpload(data) {
+		return domain.Photo{}, domain.ErrPhotoInvalid
+	}
+	if date == 0 {
+		date = int(time.Now().Unix())
+	}
+	photo, err := s.createAvatarPhoto(ctx, data, ownerID)
+	if err != nil {
+		return domain.Photo{}, err
+	}
+	if err := s.media.AddProfilePhotoKind(ctx, ownerType, ownerID, domain.ProfilePhotoKindProfile, photo.ID, date); err != nil {
+		return domain.Photo{}, err
+	}
+	return photo, nil
+}
+
+// photoSourceBytes reads the original image bytes behind a stored photo. Every
+// static size of a photo written by putPhotoStaticSizes points at the same
+// stored object, so any one size yields the full image.
+func (s *Service) photoSourceBytes(ctx context.Context, photo domain.Photo) ([]byte, bool) {
+	for _, size := range photo.Sizes {
+		if size.Type == "" {
+			continue
+		}
+		key := fmt.Sprintf("photo:%d:%s", photo.ID, size.Type)
+		blob, found, err := s.media.GetFileBlob(ctx, key)
+		if err != nil || !found || blob.Size <= 0 || blob.Size > maxBotAvatarSourceBytes {
+			continue
+		}
+		backend, err := s.backendFor(blob.Backend)
+		if err != nil {
+			continue
+		}
+		body, total, err := backend.GetRange(ctx, blob.ObjectKey, 0, blob.Size)
+		if err != nil || total != blob.Size || int64(len(body)) != blob.Size {
+			s.log.Warn("read bot avatar source blob failed", zap.String("location_key", key), zap.Error(err))
+			continue
+		}
+		return body, true
+	}
+	return nil, false
+}