feat: add lead-only status change rule for boards and update related logic

backend/migrations/versions/1a7b2c3d4e5f_add_board_lead_only_status_change_rule.py

@@ -0,0 +1,43 @@
+"""add lead-only status change board rule
+
+Revision ID: 1a7b2c3d4e5f
+Revises: c2e9f1a6d4b8
+Create Date: 2026-02-13 00:00:00.000000
+
+"""
+
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "1a7b2c3d4e5f"
+down_revision = "fa6e83f8d9a1"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    inspector = sa.inspect(bind)
+    board_columns = {column["name"] for column in inspector.get_columns("boards")}
+    if "only_lead_can_change_status" not in board_columns:
+        op.add_column(
+            "boards",
+            sa.Column(
+                "only_lead_can_change_status",
+                sa.Boolean(),
+                nullable=False,
+                server_default=sa.false(),
+            ),
+        )
+
+
+def downgrade() -> None:
+    bind = op.get_bind()
+    inspector = sa.inspect(bind)
+    board_columns = {column["name"] for column in inspector.get_columns("boards")}
+    if "only_lead_can_change_status" in board_columns:
+        op.drop_column("boards", "only_lead_can_change_status")