rebase

app/migrations/seed.py

@@ -245,7 +245,12 @@ BUILTIN_PRESETS = [FANTASY_PRESET, SCI_FI_PRESET]
 
 
 async def seed_builtin_presets(session: AsyncSession) -> None:
-    """Insert builtin presets if they don't yet exist. Owned by the first admin (or a system sentinel)."""
+    """Insert builtin presets if they don't yet exist.
+
+    Builtin presets have owner_id=NULL (they are system presets, not owned by
+    any specific user). This avoids the FK violation that occurred on first
+    startup when no admin user existed yet.
+    """
     for preset_data in BUILTIN_PRESETS:
         existing = (
             await session.execute(
@@ -254,18 +259,8 @@ async def seed_builtin_presets(session: AsyncSession) -> None:
         ).scalar_one_or_none()
         if existing is not None:
             continue
-        # Find any admin to own the preset, or use a sentinel UUID
-        from app.models import User
-        from sqlalchemy import func
-
-        admin = (
-            await session.execute(
-                select(User).where(User.is_admin.is_(True)).limit(1)
-            )
-        ).scalar_one_or_none()
-        owner_id = admin.id if admin else uuid.UUID("00000000-0000-0000-0000-000000000001")
         preset = WorldPreset(
-            owner_id=owner_id,
+            owner_id=None,  # system preset — no owner
             **preset_data,
             version=1,
         )