refactor(training): 培训数据层并入唯一总库 app.db（非运行态建表/种子，全列可空）

- 训练 ORM 模型改名回旧表名(accounts/events/bookings/tests/courses/policy_logs/plan_logs/survey_logs)
  并全列可空（兼容按部分字段插入）；alembic 0003 丢弃重建并入唯一总库。
- training/db.py 指向 app.db、移除运行时 init_db；main.py lifespan 移除 init_db。
- seed.py 增培训种子(超管账号/排期/在线课程, 幂等)。
- 验证(真实库 migrate+seed+TestClient)：auth/me、admin/*、park/*、training /api/health|events|courses 全 200。

alembic/versions/0003_training_tables.py

@@ -0,0 +1,40 @@
+"""培训业务表并入唯一总库（accounts/events/bookings/tests/courses/policy_logs/plan_logs/survey_logs，全列可空）
+
+Revision ID: 0003_training_tables
+Revises: 0002_park_screen_bind
+Create Date: 2026-08-24
+"""
+from __future__ import annotations
+
+import sys
+import os
+from alembic import op
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))))
+
+revision = "0003_training_tables"
+down_revision = "0002_park_screen_bind"
+branch_labels = None
+depends_on = None
+
+_TABLES = ["accounts", "events", "bookings", "tests", "courses", "policy_logs", "plan_logs", "survey_logs"]
+
+
+def upgrade() -> None:
+    # 培训表并入 app.db；若此前残留旧表则丢弃后按当前（可空列）模型重建
+    for t in _TABLES:
+        try:
+            op.drop_table(t)
+        except Exception:  # 表不存在则忽略
+            pass
+    from app.infrastructure.db import Base
+    import app.infrastructure.models  # noqa: F401
+    Base.metadata.create_all(bind=op.get_bind())
+
+
+def downgrade() -> None:
+    for t in _TABLES:
+        try:
+            op.drop_table(t)
+        except Exception:
+            pass