Add a platform-aware route target system so a single route can forward
to several destinations at once (e.g. a Discord channel and a Telegram
group). Route.target becomes Route.targets[] with per-entry platform,
channelId/threadId for Discord and chatId/topicId for Telegram; the
legacy single-target format is normalized on load and accepted by the
admin API.
Implement the Telegram driver with HTML rendering and Bot API
sendMessage (chat_id + message_thread_id for topics, retry on 429/5xx),
plus /gh commands served over POST /telegram/webhook: login, logout,
comment, merge and close. The comment/merge/close commands resolve the
issue or PR from the replied-to notification message. OAuth binding now
stores a D1 telegram_links mapping and replies with a confirmation.
Sync the Telegram webhook from the scheduled trigger via setWebhook.
Document the /gh login, /gh logout and /gh comment add|edit|del
commands plus the right-click message context-menu equivalents, and
require the applications.commands invite scope. Comments are posted as
the linked user's own GitHub account, so the old GitHub App identity,
Message Content intent and Read Message History requirements are gone.
