Bot.ID(): silent return of 0 on invalid or malformed token

[Zoomish]

Problem

Bot.ID() parses the numeric bot id from the token prefix (<id>:<secret>). On any parse error it returns 0 with no way for callers to distinguish:

• invalid / placeholder token,
• corrupted token string,
• API misuse,

from a legitimate bot id that might theoretically collide with 0 (or simply: callers assume 0 means “error” but this is undocumented).

Current implementation:

func (b *Bot) ID() int64 {
	id, err := strconv.ParseInt(strings.Split(b.token, ":")[0], 10, 64)
	if err != nil {
		return 0
	}
	return id
}