chore: import upstream snapshot with attribution

apps/webapp/app/services/dashboardAgentDb.server.ts

@@ -0,0 +1,20 @@
+import { createDashboardAgentDb, type DashboardAgentDb } from "@internal/dashboard-agent-db";
+import { env } from "~/env.server";
+import { singleton } from "~/utils/singleton";
+
+/**
+ * The webapp's connection to the dashboard-agent conversation store (the History
+ * tab + the chat panel's create / rename / delete / resume actions). Same Drizzle
+ * client the agent task uses, pointed at the same database.
+ *
+ * This is the agent's OWN datastore — NOT the main Prisma database, which the
+ * agent has no access to. Cloud uses the dedicated PlanetScale database; OSS
+ * falls back to DATABASE_URL with tables isolated in the `trigger_dashboard_agent`
+ * schema.
+ */
+export const dashboardAgentDb: DashboardAgentDb = singleton("dashboardAgentDb", () => {
+  const connectionString = env.DASHBOARD_AGENT_DATABASE_URL ?? env.DATABASE_URL;
+  return createDashboardAgentDb(connectionString, {
+    max: env.DATABASE_CONNECTION_LIMIT,
+  }).db;
+});