database: add indexes for model alias resolution

- Create indexes on provider_model_name and provider_model_aliases
- Optimize model lookup performance for direct match and alias resolution
- Support efficient JSONB queries on provider_model_aliases

alembic/versions/20251215_0950_6d0a5273f0f1_add_indexes_for_model_alias_resolution.py

@@ -0,0 +1,47 @@
+"""add_indexes_for_model_alias_resolution
+
+Revision ID: 6d0a5273f0f1
+Revises: e9b3d63f0cbf
+Create Date: 2025-12-15 09:50:23.423477+00:00
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '6d0a5273f0f1'
+down_revision = 'e9b3d63f0cbf'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """应用迁移：升级到新版本"""
+    # 为 Model 表添加索引，优化别名解析性能
+
+    # 1. provider_model_name 索引（支持精确匹配）
+    op.create_index(
+        "idx_model_provider_model_name",
+        "Model",
+        ["provider_model_name"],
+        unique=False,
+        postgresql_where=sa.text("is_active = true"),
+    )
+
+    # 2. provider_model_aliases JSONB GIN 索引（支持 JSONB 查询，仅 PostgreSQL）
+    # GIN 索引可以加速 @> 操作符的查询
+    op.execute(
+        """
+        CREATE INDEX IF NOT EXISTS idx_model_provider_model_aliases_gin
+        ON "Model" USING gin(provider_model_aliases)
+        WHERE is_active = true
+        """
+    )
+
+
+def downgrade() -> None:
+    """回滚迁移：降级到旧版本"""
+    # 删除索引
+    op.drop_index("idx_model_provider_model_name", table_name="Model")
+    op.execute('DROP INDEX IF EXISTS idx_model_provider_model_aliases_gin')