chore: add a concept (and enforcement of) read-only blocks (#2161)

alembic/versions/220856bbf43b_add_read_only_column.py

@@ -0,0 +1,35 @@
+"""add read-only column
+
+Revision ID: 220856bbf43b
+Revises: 1dc0fee72dea
+Create Date: 2025-05-13 14:42:17.353614
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "220856bbf43b"
+down_revision: Union[str, None] = "1dc0fee72dea"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # add default value of `False`
+    op.add_column("block", sa.Column("read_only", sa.Boolean(), nullable=True))
+    op.execute(
+        f"""
+        UPDATE block
+        SET read_only = False
+    """
+    )
+    op.alter_column("block", "read_only", nullable=False)
+
+
+def downgrade() -> None:
+    op.drop_column("block", "read_only")