docs(session): explain indefinite native session fields

.changeset/docs-native-session-deadlines.md

@@ -0,0 +1,2 @@
+---
+---

packages/backend/src/api/resources/Session.ts

@@ -52,9 +52,13 @@ export class Session {
     readonly status: string,
     /** The time the session was last active on the [`Client`](https://clerk.com/docs/reference/backend/types/backend-client). */
     readonly lastActiveAt: number,
-    /** The Unix timestamp when the `Session` will expire. */
+    /**
+     * The Unix timestamp when the `Session` will expire. For an [indefinite native session](https://clerk.com/docs/guides/secure/session-options#native-sessions), this is `0`, meaning no expiration deadline. Check `status` to determine whether the session is active.
+     */
     readonly expireAt: number,
-    /** The Unix timestamp when the `Session` will be abandoned. */
+    /**
+     * The Unix timestamp when the `Session` will be abandoned. For an [indefinite native session](https://clerk.com/docs/guides/secure/session-options#native-sessions), this is `0`, meaning no abandonment deadline.
+     */
     readonly abandonAt: number,
     /** The Unix timestamp when the `Session` was first created. */
     readonly createdAt: number,

packages/shared/src/types/session.ts

@@ -221,15 +221,15 @@ export interface SessionResource extends ClerkResource {
    */
   status: SessionStatus;
   /**
-   * The date and time when the session will expire. Unix epoch zero means no maximum lifetime.
+   * The date and time when the session will expire. For an [indefinite native session](https://clerk.com/docs/guides/secure/session-options#native-sessions), this represents Unix epoch zero, meaning no expiration deadline is configured.
    */
   expireAt: Date;
   /**
    * Whether the session has a maximum lifetime. `false` when `expireAt` is Unix epoch zero. A session without a maximum lifetime can still end through sign-out or revocation, so use `status` to check whether it is active. `undefined` in ClerkJS versions that predate this property.
    */
   readonly hasMaximumLifetime?: boolean;
   /**
-   * The abandonment deadline. Unix epoch zero means no abandonment deadline.
+   * The abandonment deadline. For an [indefinite native session](https://clerk.com/docs/guides/secure/session-options#native-sessions), this represents Unix epoch zero, meaning no abandonment deadline is configured.
    */
   abandonAt: Date;
   /**