fix(telegram): answer callback queries immediately to prevent retries

Telegram retries callback queries if they aren't acknowledged quickly.
Previously, answerCallbackQuery was called in a finally block AFTER
processing, which could take several seconds for agent responses.

This change moves answerCallbackQuery to immediately after basic
validation, before any processing begins. This prevents Telegram
from sending duplicate callbacks while the agent is thinking.

Fixes duplicate callback handling when agent processing is slow.

src/telegram/bot-handlers.ts

@@ -179,6 +179,8 @@ export const registerTelegramHandlers = ({
     const callback = ctx.callbackQuery;
     if (!callback) return;
     if (shouldSkipUpdate(ctx)) return;
+    // Answer immediately to prevent Telegram from retrying while we process
+    await bot.api.answerCallbackQuery(callback.id).catch(() => {});
     try {
       const data = (callback.data ?? "").trim();
       const callbackMessage = callback.message;
@@ -323,8 +325,6 @@ export const registerTelegramHandlers = ({
       });
     } catch (err) {
       runtime.error?.(danger(`callback handler failed: ${String(err)}`));
-    } finally {
-      await bot.api.answerCallbackQuery(callback.id).catch(() => {});
     }
   });