feat(telegram): implement resolveChannelName via getChat API

Enables the channel-approval flow to show the Telegram group name
in the approval card instead of a generic "a telegram channel".

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/channels/telegram.ts

@@ -216,6 +216,21 @@ registerChannelAdapter('telegram', {
 
     const wrapped: ChannelAdapter = {
       ...bridge,
+      resolveChannelName: async (platformId: string) => {
+        const chatId = platformId.split(':').slice(1).join(':');
+        if (!chatId) return null;
+        try {
+          const res = await fetch(`https://api.telegram.org/bot${token}/getChat`, {
+            method: 'POST',
+            headers: { 'content-type': 'application/json' },
+            body: JSON.stringify({ chat_id: chatId }),
+          });
+          const data = (await res.json()) as { ok?: boolean; result?: { title?: string } };
+          return data.ok ? (data.result?.title ?? null) : null;
+        } catch {
+          return null;
+        }
+      },
       async setup(hostConfig: ChannelSetup) {
         const intercepted: ChannelSetup = {
           ...hostConfig,