fix: auto-prefix platform IDs in register.ts to match Chat SDK format

Chat SDK adapters use prefixed platform IDs (e.g. "telegram:6037840640",
"discord:guildId:channelId") but users provide raw IDs during setup.
Without the prefix, the router can't match the registered messaging group
to incoming messages and silently drops them.

register.ts now auto-prefixes with the channel type if not already present.

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

docs/v2-checklist.md

@@ -43,7 +43,7 @@ Status: [x] done, [~] partial, [ ] not started
 - [x] Chat SDK SQLite state adapter (KV, subscriptions, locks, lists)
 - [x] Discord via Chat SDK
 - [~] Slack via Chat SDK (adapter + skill written, not tested)
-- [~] Telegram via Chat SDK (adapter + skill written, not tested)
+- [x] Telegram via Chat SDK (E2E verified: inbound, routing, typing, delivery)
 - [~] Microsoft Teams via Chat SDK (adapter + skill written, not tested)
 - [~] Google Chat via Chat SDK (adapter + skill written, not tested)
 - [~] Linear via Chat SDK (adapter + skill written, not tested)

setup/register.ts

@@ -118,6 +118,13 @@ export async function run(args: string[]): Promise<void> {
     process.exit(4);
   }
 
+  // Chat SDK adapters prefix platform IDs with the channel type (e.g. "telegram:123",
+  // "discord:guild:channel"). Auto-prefix if the user provided a raw ID so the router
+  // matches the adapter's format.
+  if (parsed.platformId && !parsed.platformId.startsWith(`${parsed.channel}:`)) {
+    parsed.platformId = `${parsed.channel}:${parsed.platformId}`;
+  }
+
   log.info('Registering channel', parsed);
 
   // Init v2 central DB