feat(msteams): make ref pruning configurable and atomic

docs/chat-apps.md

@@ -642,7 +642,10 @@ Create or reuse a Microsoft Teams / Azure bot app registration. Set the bot mess
       "allowFrom": ["*"],
       "replyInThread": true,
       "mentionOnlyResponse": "Hi — what can I help with?",
-      "validateInboundAuth": true
+      "validateInboundAuth": true,
+      "refTtlDays": 30,
+      "pruneWebChatRefs": true,
+      "pruneNonPersonalRefs": true
     }
   }
 }
@@ -651,7 +654,9 @@ Create or reuse a Microsoft Teams / Azure bot app registration. Set the bot mess
 > - `replyInThread: true` replies to the triggering Teams activity when a stored `activity_id` is available.
 > - `mentionOnlyResponse` controls what Nanobot receives when a user sends only a bot mention (`<at>Nanobot</at>`). Set to `""` to ignore mention-only messages.
 > - `validateInboundAuth: true` enables inbound Bot Framework bearer-token validation (signature, issuer, audience, lifetime, `serviceUrl`). This is the safe default for public deployments. Only set it to `false` for local development or tightly controlled testing.
-> - Conversation refs are auto-pruned to avoid bad outbound routing: Web Chat refs, non-`personal` refs, and refs older than 30 days are removed.
+> - `refTtlDays` (default `30`) controls how old stored conversation refs can be before they are pruned.
+> - `pruneWebChatRefs` (default `true`) drops refs with `webchat.botframework.com` service URLs.
+> - `pruneNonPersonalRefs` (default `true`) drops refs whose `conversation_type` is not `personal`.
 
 **4. Run**