fix: add nma_pk_location to thing_version table

SQLAlchemy-continuum creates a thing_version table that mirrors
the thing table structure. The migration must add the new column
to both tables for versioning to work correctly.

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

Author: kbighorse

alembic/versions/76e3ae8b99cb_enforce_thing_fk_for_nma_legacy_models.py

@@ -29,7 +29,7 @@
 
 def upgrade() -> None:
     """Upgrade schema to enforce Thing FK relationships."""
-    # 1. Add nma_pk_location column to thing table
+    # 1. Add nma_pk_location column to thing table and its version table
     op.add_column(
         "thing",
         sa.Column(
@@ -39,6 +39,14 @@ def upgrade() -> None:
             comment="To audit the original NM_Aquifer LocationID if it was transferred over",
         ),
     )
+    op.add_column(
+        "thing_version",
+        sa.Column(
+            "nma_pk_location",
+            sa.String(),
+            nullable=True,
+        ),
+    )
 
     # 2. Make thing_id NOT NULL on NMA_AssociatedData
     # First, delete any orphan records (records without a thing_id)
@@ -57,8 +65,9 @@ def upgrade() -> None:
 
 def downgrade() -> None:
     """Downgrade schema to allow nullable thing_id."""
-    # 1. Remove nma_pk_location column from thing table
+    # 1. Remove nma_pk_location column from thing table and its version table
     op.drop_column("thing", "nma_pk_location")
+    op.drop_column("thing_version", "nma_pk_location")
 
     # 2. Make thing_id nullable on NMA_AssociatedData
     op.alter_column(