feat: db migration for hit tracking

alembic/versions/2026-05-21_adds_hits.py

@@ -0,0 +1,27 @@
+"""adds hits
+
+Revision ID: 0b42b25de259
+Revises: e723dddd82db
+Create Date: 2026-05-21 16:16:52.147050
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "0b42b25de259"
+down_revision = "e723dddd82db"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column("mirror", sa.Column("hits", sa.Integer(), nullable=True))
+    op.execute("UPDATE mirror SET hits = 0")
+    op.alter_column("mirror", "hits", nullable=False)
+
+
+def downgrade() -> None:
+    op.drop_column("mirror", "hits")