fix: add merge migration for alembic heads and make remove_is_builtin idempotent

- Create merge migration f3d2dc90ba3a to merge single_interface and clone_mode heads
- Make remove_is_builtin migration idempotent with IF EXISTS clause

Refs: alembic migration fix for dev branch

apps/api/alembic/versions/2026_05_23_remove_is_builtin.py

@@ -10,14 +10,14 @@ import sqlalchemy as sa
 
 # revision identifiers, used by Alembic.
 revision = '2026_05_23_remove_is_builtin'
-down_revision = '2026_05_22_add_clone_mode'
+down_revision = 'f3d2dc90ba3a'
 branch_labels = None
 depends_on = None
 
 
 def upgrade() -> None:
     # Drop the is_builtin column from tool_types
-    op.drop_column('tool_types', 'is_builtin')
+    op.execute("ALTER TABLE tool_types DROP COLUMN IF EXISTS is_builtin")
 
 
 def downgrade() -> None:

apps/api/alembic/versions/f3d2dc90ba3a_merge_single_interface_and_clone_mode.py

@@ -0,0 +1,25 @@
+"""merge_single_interface_and_clone_mode
+
+Revision ID: f3d2dc90ba3a
+Revises: 0015_single_interface, 2026_05_22_add_clone_mode
+Create Date: 2026-05-24 10:43:14.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "f3d2dc90ba3a"
+down_revision: Union[str, Sequence[str], None] = ("0015_single_interface", "2026_05_22_add_clone_mode")
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    pass
+
+
+def downgrade() -> None:
+    pass