fix(telegram): start polling after webhook cleanup timeout (#76735)

Summary:
- The branch changes Telegram polling startup to reuse the successful probe `getMe` result as grammY `botInfo` ... es` after recoverable `deleteWebhook` failures, and updates Telegram docs, changelog, and regression tests.
- Reproducibility: yes. for the narrow PR bug: source inspection shows current main can block before polling o ... d timeout coverage that reaches `run()`. The full linked high-RTT report remains only partially reproduced.

Automerge notes:
- Ran the ClawSweeper repair loop before final review.
- Included post-review commit in the final squash: fix(telegram): start polling after webhook cleanup timeout
- Included post-review commit in the final squash: fix(telegram): extract bot info contract

Validation:
- ClawSweeper review passed for head c74bbdd1ff.
- Required merge gates passed before the squash merge.

Prepared head SHA: c74bbdd1ff
Review: https://github.com/openclaw/openclaw/pull/76735#issuecomment-4366417178

Co-authored-by: Ayaan Zaidi <hi@obviy.us>
Co-authored-by: Peter Steinberger <steipete@gmail.com>

docs/channels/telegram.md

@@ -855,7 +855,8 @@ Per-account, per-group, and per-topic overrides are supported (same inheritance
     - `getMe returned 401` is a Telegram authentication failure for the configured bot token.
     - Re-copy or regenerate the bot token in BotFather, then update `channels.telegram.botToken`, `channels.telegram.tokenFile`, `channels.telegram.accounts.<id>.botToken`, or `TELEGRAM_BOT_TOKEN` for the default account.
     - `deleteWebhook 401 Unauthorized` during startup is also an auth failure; treating it as "no webhook exists" would only defer the same bad-token failure to later API calls.
-    - If `deleteWebhook` fails with a transient network error during polling startup, OpenClaw checks `getWebhookInfo`; when Telegram reports an empty webhook URL, polling continues because cleanup is already satisfied.
+    - If `deleteWebhook` fails with a transient network error during polling startup, OpenClaw continues into long polling instead of making another pre-poll control-plane call. A still-active webhook surfaces as a `getUpdates` conflict; OpenClaw then rebuilds the Telegram transport and retries webhook cleanup.
+    - After a successful startup `getMe` probe, OpenClaw reuses that bot identity for grammY polling startup so the runner does not need a second `getMe` before the first `getUpdates`.
 
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