fix: Remove FK constraint from location migration for SQLite compatibility

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

migrations/versions/2025_01_21_0100-e5f6g7h8i9j0_add_hierarchical_locations.py

@@ -35,26 +35,17 @@ def upgrade() -> None:
     op.create_index(op.f("ix_location_id"), "location", ["id"], unique=False)
     op.create_index(op.f("ix_location_parent_id"), "location", ["parent_id"], unique=False)
 
-    # Add location_id column to spool table
+    # Add location_id column to spool table (SQLite compatible - no FK constraint)
     op.add_column(
         "spool",
         sa.Column("location_id", sa.Integer(), nullable=True),
     )
-    op.create_foreign_key(
-        "fk_spool_location_id",
-        "spool",
-        "location",
-        ["location_id"],
-        ["id"],
-        ondelete="SET NULL",
-    )
     op.create_index(op.f("ix_spool_location_id"), "spool", ["location_id"], unique=False)
 
 
 def downgrade() -> None:
     """Drop location table and remove location_id from spool."""
     op.drop_index(op.f("ix_spool_location_id"), table_name="spool")
-    op.drop_constraint("fk_spool_location_id", "spool", type_="foreignkey")
     op.drop_column("spool", "location_id")
     op.drop_index(op.f("ix_location_parent_id"), table_name="location")
     op.drop_index(op.f("ix_location_id"), table_name="location")