fix(webapp): isolate chat-snapshot key helper from db.server import chain

The integration tests for chat snapshot + replay-after-crash imported
`chatSnapshotStoragePathForSession` from sessions.server.ts, which
transitively pulls in `~/db.server` and constructs the singleton
PrismaClient. In CI the testcontainer Postgres is on a random port, so
the eager Prisma client throws `P1001: Can't reach database server at
localhost:5432` as an unhandled rejection — tests pass but vitest exits
non-zero.

Extract the helper into its own `chatSnapshot.server.ts` module that
only depends on env.server. Update the route, session create handler,
and both integration tests to import from the new location. No
behavior change.

Author: ericallam

apps/webapp/app/routes/api.v1.sessions.$sessionId.snapshot-url.ts

@@ -1,10 +1,8 @@
 import { json } from "@remix-run/server-runtime";
 import { z } from "zod";
 import { $replica } from "~/db.server";
-import {
-  chatSnapshotStoragePathForSession,
-  resolveSessionByIdOrExternalId,
-} from "~/services/realtime/sessions.server";
+import { chatSnapshotStoragePathForSession } from "~/services/realtime/chatSnapshot.server";
+import { resolveSessionByIdOrExternalId } from "~/services/realtime/sessions.server";
 import {
   createActionApiRoute,
   createLoaderApiRoute,

apps/webapp/app/routes/api.v1.sessions.ts

@@ -17,10 +17,8 @@ import {
   ensureRunForSession,
   type SessionTriggerConfig,
 } from "~/services/realtime/sessionRunManager.server";
-import {
-  chatSnapshotStoragePathForSession,
-  serializeSession,
-} from "~/services/realtime/sessions.server";
+import { chatSnapshotStoragePathForSession } from "~/services/realtime/chatSnapshot.server";
+import { serializeSession } from "~/services/realtime/sessions.server";
 import { SessionsRepository } from "~/services/sessionsRepository/sessionsRepository.server";
 import {
   anyResource,

apps/webapp/app/services/realtime/chatSnapshot.server.ts

@@ -0,0 +1,13 @@
+import { env } from "~/env.server";
+
+/**
+ * Canonical storage URI for a session's chat.agent snapshot. Stamped on
+ * `Session.chatSnapshotStoragePath` at row creation so PUT/GET presigns
+ * resolve to the same store even if `OBJECT_STORE_DEFAULT_PROTOCOL`
+ * changes later.
+ */
+export function chatSnapshotStoragePathForSession(friendlyId: string): string {
+  const path = `sessions/${friendlyId}/snapshot.json`;
+  const protocol = env.OBJECT_STORE_DEFAULT_PROTOCOL;
+  return protocol ? `${protocol}://${path}` : path;
+}

apps/webapp/app/services/realtime/sessions.server.ts

@@ -1,20 +1,6 @@
 import type { PrismaClient, Session } from "@trigger.dev/database";
 import type { SessionItem } from "@trigger.dev/core/v3";
 import { $replica } from "~/db.server";
-import { env } from "~/env.server";
-
-/**
- * Canonical storage URI for a session's chat.agent snapshot. Stamped on
- * `Session.chatSnapshotStoragePath` at row creation so PUT/GET presigns
- * resolve to the same store even if `OBJECT_STORE_DEFAULT_PROTOCOL`
- * changes later. The protocol prefix (when set) is what makes
- * generic-packets PUT and GET agree on the target provider.
- */
-export function chatSnapshotStoragePathForSession(friendlyId: string): string {
-  const path = `sessions/${friendlyId}/snapshot.json`;
-  const protocol = env.OBJECT_STORE_DEFAULT_PROTOCOL;
-  return protocol ? `${protocol}://${path}` : path;
-}
 
 /**
  * Prefix that {@link SessionId.generate} attaches to every Session friendlyId.

apps/webapp/test/chat-snapshot-integration.test.ts

@@ -26,7 +26,7 @@ import {
 import type { UIMessage } from "ai";
 import { afterEach, describe, expect, vi } from "vitest";
 import { env } from "~/env.server";
-import { chatSnapshotStoragePathForSession } from "~/services/realtime/sessions.server";
+import { chatSnapshotStoragePathForSession } from "~/services/realtime/chatSnapshot.server";
 import { generatePresignedUrl } from "~/v3/objectStore.server";
 
 vi.setConfig({ testTimeout: 60_000 });

apps/webapp/test/replay-after-crash.test.ts

@@ -33,7 +33,7 @@ import {
 import type { UIMessageChunk } from "ai";
 import { afterEach, describe, expect, vi } from "vitest";
 import { env } from "~/env.server";
-import { chatSnapshotStoragePathForSession } from "~/services/realtime/sessions.server";
+import { chatSnapshotStoragePathForSession } from "~/services/realtime/chatSnapshot.server";
 import { generatePresignedUrl } from "~/v3/objectStore.server";
 
 vi.setConfig({ testTimeout: 60_000 });