fix: persist direct chat transcript before Goosed escalation

Prevent portal direct-chat history from being lost when snapshot cache
is invalidated on Goosed submit by writing non-empty messages to DB first,
and stop caching empty Goose placeholder messages in snapshots.

Co-authored-by: Cursor <cursoragent@cursor.com>

session-snapshot.mjs

@@ -67,6 +67,8 @@ function resolveDisplayTitle(session, messages) {
   return deriveTitleFromMessages(messages);
 }
 
+import { filterNonemptyUserVisibleMessages } from './conversation-transcript-persist.mjs';
+
 async function syncConversationMemory({
   memoryV2 = null,
   conversationMemoryService = null,
@@ -279,9 +281,8 @@ export function createSessionSnapshotService(pool, options = {}) {
       });
       if (!res.ok) return;
       const gooseSession = await res.json();
-      // Store raw userVisible messages — same as write-through path.
-      const messages = (gooseSession.conversation ?? [])
-        .filter((m) => m.metadata?.userVisible);
+      // Store userVisible messages with content — skip empty Goose placeholders.
+      const messages = filterNonemptyUserVisibleMessages(gooseSession.conversation ?? []);
       await save(sessionId, userId, gooseSession, messages);
     } catch (err) {
       console.warn('[snapshot] refresh failed:', sessionId, err instanceof Error ? err.message : err);