docs: align agent auth model and fix session test

apps/mcp-server/src/session.rs

@@ -340,7 +340,7 @@ mod tests {
         Executor,
         postgres::{PgConnectOptions, PgPoolOptions},
     };
-    use time::format_description::well_known::Rfc3339;
+    use time::{OffsetDateTime, format_description::well_known::Rfc3339};
     use uuid::Uuid;
 
     use super::{
@@ -353,6 +353,12 @@ mod tests {
         time::OffsetDateTime::parse(value, &Rfc3339).unwrap()
     }
 
+    fn truncate_to_micros(value: OffsetDateTime) -> OffsetDateTime {
+        value
+            .replace_nanosecond((value.nanosecond() / 1_000) * 1_000)
+            .unwrap()
+    }
+
     #[tokio::test]
     async fn creates_and_reads_transport_sessions() {
         let store = InMemorySessionStore::default();
@@ -455,15 +461,15 @@ mod tests {
         .await
         .unwrap();
 
-        let created_at = timestamp("2026-05-01T10:00:00Z");
-        let initialized_at = timestamp("2026-05-01T10:00:05Z");
+        let created_at = OffsetDateTime::now_utc() - time::Duration::hours(1);
+        let initialized_at = created_at + time::Duration::seconds(5);
         let session_id = store_a
             .create(
                 "2025-11-25",
                 "default",
                 "sales",
                 created_at,
-                Some(timestamp("2026-05-02T10:00:00Z")),
+                Some(created_at + time::Duration::days(30)),
             )
             .await
             .unwrap();
@@ -482,7 +488,7 @@ mod tests {
 
         assert_eq!(session.id, session_id);
         assert!(session.initialized);
-        assert_eq!(session.updated_at, initialized_at);
+        assert_eq!(session.updated_at, truncate_to_micros(initialized_at));
         assert_eq!(session.workspace_slug, "default");
         assert_eq!(session.agent_slug, "sales");
     }