Telegram: gate implicit topic replies behind a config flag

[strk-ai-agent]

Adds a new telegram.respondToImplicitTopicReplies flag (default true).

When set to false, the bot in a forum supergroup topic with threadIsolation: true only answers messages that match:

• the configured trigger (e.g. !oc ...),
• an @botname mention (when respondToMentions: true, default),
• a swipe-reply to the bot's own message (when respondToReplies: true, default), or
• an attachment (caption-less in a DM or in an active topic).

Plain messages in an active topic are dropped, while per-topic session isolation is preserved. Set respondToMentions: false and respondToReplies: false too if you want only trigger-prefixed messages and attachment-bearing messages to be forwarded.

Implementation notes:

• The decision tree in handleUpdate is extracted into a pure resolveTelegramQuery helper so the new flag is covered by unit tests in isolation from the Telegram Bot API and the session manager.
• 27 new unit tests in tests/unit/telegram-resolve-query.test.ts cover the routing rules, including the new flag.
• README / docs already document how respondToMentions and respondToReplies work; this PR adds a parallel respondToImplicitTopicReplies to docs/TELEGRAM_SETUP.md.

Verification:

• bun run typecheck
• bun run check:connectors
• bun test (383 pass, 0 fail)

[strk]

I've tested and am successfully using this feature. It's backward compatible (nothing changes unless you add a new configuration). I can finally have Telegram topics w/out the bot answering every single line

Approved !