fix(database): batch session activity persistence (#1539)

src/backend/database/repositories/factory.ts

@@ -278,6 +278,10 @@ export function createCurrentSessionRepository(): SessionRepository {
   return new SessionRepository(
     createCurrentRepositoryContext(),
     createCurrentRepositoryWriteHook("session_repository_write"),
+    // Activity timestamps are informational; the periodic flush persists them.
+    needsExplicitPersist(resolveDatabaseDialect())
+      ? () => DatabaseSaveTrigger.markDirty()
+      : undefined,
   );
 }
 

src/backend/database/repositories/session-repository.ts

@@ -13,6 +13,8 @@ export class SessionRepository {
   constructor(
     private readonly context: DatabaseContext,
     private readonly onWrite?: () => void | Promise<void>,
+    private readonly onActivity:
+      (() => void | Promise<void>) | undefined = onWrite,
   ) {}
 
   async create(session: NewSessionRecord): Promise<SessionRecord> {
@@ -63,7 +65,7 @@ export class SessionRepository {
       .where(and(eq(sessions.id, id), lte(sessions.lastActiveAt, cutoff)));
 
     if (rowsAffected(result) === 0) return false;
-    await this.afterWrite();
+    await this.onActivity?.();
     return true;
   }