fix(alembic): 合并 invite_fingerprint 与 044 双 head 修复 Multiple heads 部署失败

#31 的 invite_fingerprint_table 迁移 down_revision 挂在 0cf18d590b1d，与 #30
的 044dce6e9b1f(ad_reward+withdraw 合并) 形成并列双 head，alembic upgrade head
报 "Multiple head revisions are present"，ecs1 部署在迁移步失败未重启。

加纯合并迁移 a8c47fc4dc39 (Revises: invite_fingerprint_table, 044dce6e9b1f)
收敛为单 head，upgrade/downgrade 为 no-op 不改 schema。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

alembic/versions/a8c47fc4dc39_merge_invite_fingerprint_and_ad_reward_.py

@@ -0,0 +1,26 @@
+"""merge invite_fingerprint and ad_reward heads
+
+Revision ID: a8c47fc4dc39
+Revises: invite_fingerprint_table, 044dce6e9b1f
+Create Date: 2026-06-10 01:03:03.699443
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'a8c47fc4dc39'
+down_revision: Union[str, Sequence[str], None] = ('invite_fingerprint_table', '044dce6e9b1f')
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    pass
+
+
+def downgrade() -> None:
+    pass