The "Manage Bot" button on a bot's profile deep-links to @BotFather with
start=<bot username>. parseBotCommand dropped the argument, so /start <bot>
just replied with the generic greeting instead of the per-bot menu.
Route "/start <arg>" to the bot's "What do you want to do?" screen (same as
/mybots then tapping the bot) when <arg> names one of the sender's own bots by
username or id; empty or unknown args keep the greeting.
- Edit Bot now shows the current value of every field (Name/About/
Description/Botpic/Commands) like BotFather, with real botpic status
via a new PeerHasAvatar port method.
- After editing a field the dialog lands back on a fresh Edit Bot menu
(working "Back to bot" / "Bots list" buttons) instead of ending, so a
follow-up button press no longer reports the button as expired.
- Service-bot messages now render @username as a tappable mention entity.
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.
