Add per-user active session counts to IAM user list

Move active_sessions field from UserDetailResponse into UserListItem
so GET /admin/users returns session counts. Uses a correlated subquery
to count non-revoked, non-expired sessions per user.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/routers/admin.py

@@ -108,12 +108,34 @@ async def list_users(
     db: AsyncSession = Depends(get_db),
     _actor: User = Depends(get_current_user),
 ):
-    """Return all users with basic stats."""
-    result = await db.execute(sa.select(User).order_by(User.created_at))
-    users = result.scalars().all()
+    """Return all users with basic stats including active session counts."""
+    active_sub = (
+        sa.select(sa.func.count())
+        .select_from(UserSession)
+        .where(
+            UserSession.user_id == User.id,
+            UserSession.revoked == False,
+            UserSession.expires_at > datetime.now(),
+        )
+        .correlate(User)
+        .scalar_subquery()
+    )
+
+    result = await db.execute(
+        sa.select(User, active_sub.label("active_sessions"))
+        .order_by(User.created_at)
+    )
+    rows = result.all()
+
     return UserListResponse(
-        users=[UserListItem.model_validate(u) for u in users],
-        total=len(users),
+        users=[
+            UserListItem(
+                **UserListItem.model_validate(user).model_dump(exclude={"active_sessions"}),
+                active_sessions=count,
+            )
+            for user, count in rows
+        ],
+        total=len(rows),
     )
 
 

backend/app/schemas/admin.py

@@ -27,6 +27,7 @@ class UserListItem(BaseModel):
     totp_enabled: bool
     mfa_enforce_pending: bool
     created_at: datetime
+    active_sessions: int = 0
 
     model_config = ConfigDict(from_attributes=True)
 
@@ -37,7 +38,7 @@ class UserListResponse(BaseModel):
 
 
 class UserDetailResponse(UserListItem):
-    active_sessions: int
+    pass
 
 
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