fix(git): default branch convention main -> master

alembic/versions/022_default_branch_master.py

@@ -0,0 +1,41 @@
+"""Flip the projects.default_branch server-side default from 'main' to 'master'.
+
+The repositories this system drives use ``master`` as their primary branch, but
+the column's default was inherited from the ``main`` convention. Existing rows
+already hold ``master``, so this only changes the default applied to future
+inserts that omit the column.
+
+Revision ID: 022_default_branch_master
+Revises: 021_task_board_review_complete
+Create Date: 2026-06-03
+"""
+
+from __future__ import annotations
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "022_default_branch_master"
+down_revision = "021_task_board_review_complete"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.alter_column(
+        "projects",
+        "default_branch",
+        existing_type=sa.String(length=100),
+        existing_nullable=False,
+        server_default="master",
+    )
+
+
+def downgrade() -> None:
+    op.alter_column(
+        "projects",
+        "default_branch",
+        existing_type=sa.String(length=100),
+        existing_nullable=False,
+        server_default="main",
+    )