fix(db): 时间列 TIMESTAMPTZ + 热路径索引 + 状态 CHECK 约束

P1-1 base.py 时间列改 timezone=True；迁移把 16 表 created_at/updated_at
  ALTER 为 TIMESTAMPTZ（手写 USING ... AT TIME ZONE 'UTC'）。
P1-3 新增 8 个索引（chapter_reviews/chapter_digests 复合、owner_id、
  usage_ledger、rules + jobs/rules 部分索引）。
P2 chapters/foreshadow status CHECK 约束。
迁移链 ad2c4c663daf → b1a2c3d4e5f6 → c2b3d4e5f6a7，upgrade/downgrade 往返无漂移。

packages/db/migrations/versions/b1a2c3d4e5f6_timestamptz_all_time_columns.py

@@ -0,0 +1,71 @@
+"""P1-1: 时间列改 TIMESTAMPTZ (created_at / updated_at)
+
+把 16 张表的 created_at/updated_at 由 TIMESTAMP WITHOUT TIME ZONE
+改为 TIMESTAMPTZ。既有数据按服务器本地时存的裸时间一律解释为 UTC：
+`ALTER ... TYPE TIMESTAMPTZ USING <col> AT TIME ZONE 'UTC'`
+（autogenerate 不会生成 USING 子句，手写）。downgrade 反向，
+TIMESTAMPTZ → naive 时丢弃时区（按 UTC 墙钟取值）。
+
+Revision ID: b1a2c3d4e5f6
+Revises: ad2c4c663daf
+Create Date: 2026-06-21 00:00:00.000000
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from alembic import op
+
+revision: str = "b1a2c3d4e5f6"
+down_revision: str | None = "ad2c4c663daf"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+# (table, column) — 所有时间列。
+_CREATED_AT_TABLES: tuple[str, ...] = (
+    "users",
+    "projects",
+    "skills",
+    "chapter_digests",
+    "chapter_reviews",
+    "chapters",
+    "characters",
+    "jobs",
+    "provider_credentials",
+    "rules",
+    "style_fingerprint",
+    "usage_ledger",
+    "world_entities",
+    "chapter_injection",
+)
+_UPDATED_AT_TABLES: tuple[str, ...] = (
+    "projects",
+    "foreshadow",
+    "jobs",
+    "chapter_injection",
+)
+
+
+def _columns() -> list[tuple[str, str]]:
+    cols = [(t, "created_at") for t in _CREATED_AT_TABLES]
+    cols += [(t, "updated_at") for t in _UPDATED_AT_TABLES]
+    return cols
+
+
+def upgrade() -> None:
+    for table, column in _columns():
+        op.execute(
+            f"ALTER TABLE {table} "
+            f"ALTER COLUMN {column} TYPE TIMESTAMP WITH TIME ZONE "
+            f"USING {column} AT TIME ZONE 'UTC'"
+        )
+
+
+def downgrade() -> None:
+    for table, column in _columns():
+        op.execute(
+            f"ALTER TABLE {table} "
+            f"ALTER COLUMN {column} TYPE TIMESTAMP WITHOUT TIME ZONE "
+            f"USING {column} AT TIME ZONE 'UTC'"
+        )

packages/db/migrations/versions/c2b3d4e5f6a7_indexes_and_status_checks.py

@@ -0,0 +1,86 @@
+"""P1-3 + P2: 热路径索引 + 状态 CHECK 约束
+
+新增：
+- 复合索引 ix_chapter_reviews_project_chapter / ix_chapter_digests_project_chapter
+- 主访问谓词单列索引 ix_projects_owner_id / ix_usage_ledger_owner_id /
+  ix_usage_ledger_project_id / ix_rules_project_id
+- 部分索引 ix_jobs_status_running (status='running') /
+  ix_rules_global (project_id IS NULL)
+- CHECK 约束 ck_chapters_status / ck_foreshadow_status（DB 边界兜底状态机）
+
+Revision ID: c2b3d4e5f6a7
+Revises: b1a2c3d4e5f6
+Create Date: 2026-06-21 00:05:00.000000
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "c2b3d4e5f6a7"
+down_revision: str | None = "b1a2c3d4e5f6"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    # --- 复合索引（验收/评审热路径）---
+    op.create_index(
+        "ix_chapter_reviews_project_chapter",
+        "chapter_reviews",
+        ["project_id", "chapter_no", sa.text("created_at DESC")],
+        unique=False,
+    )
+    op.create_index(
+        "ix_chapter_digests_project_chapter",
+        "chapter_digests",
+        ["project_id", sa.text("chapter_no DESC")],
+        unique=False,
+    )
+    # --- 主访问谓词单列索引 ---
+    op.create_index("ix_projects_owner_id", "projects", ["owner_id"], unique=False)
+    op.create_index("ix_usage_ledger_owner_id", "usage_ledger", ["owner_id"], unique=False)
+    op.create_index("ix_usage_ledger_project_id", "usage_ledger", ["project_id"], unique=False)
+    op.create_index("ix_rules_project_id", "rules", ["project_id"], unique=False)
+    # --- 部分索引 ---
+    op.create_index(
+        "ix_jobs_status_running",
+        "jobs",
+        ["status"],
+        unique=False,
+        postgresql_where=sa.text("status = 'running'"),
+    )
+    op.create_index(
+        "ix_rules_global",
+        "rules",
+        ["id"],
+        unique=False,
+        postgresql_where=sa.text("project_id IS NULL"),
+    )
+    # --- 状态 CHECK 约束 ---
+    op.create_check_constraint(
+        "ck_chapters_status",
+        "chapters",
+        "status IN ('draft', 'accepted')",
+    )
+    op.create_check_constraint(
+        "ck_foreshadow_status",
+        "foreshadow",
+        "status IN ('OPEN', 'PARTIAL', 'CLOSED', 'OVERDUE')",
+    )
+
+
+def downgrade() -> None:
+    op.drop_constraint("ck_foreshadow_status", "foreshadow", type_="check")
+    op.drop_constraint("ck_chapters_status", "chapters", type_="check")
+    op.drop_index("ix_rules_global", table_name="rules")
+    op.drop_index("ix_jobs_status_running", table_name="jobs")
+    op.drop_index("ix_rules_project_id", table_name="rules")
+    op.drop_index("ix_usage_ledger_project_id", table_name="usage_ledger")
+    op.drop_index("ix_usage_ledger_owner_id", table_name="usage_ledger")
+    op.drop_index("ix_projects_owner_id", table_name="projects")
+    op.drop_index("ix_chapter_digests_project_chapter", table_name="chapter_digests")
+    op.drop_index("ix_chapter_reviews_project_chapter", table_name="chapter_reviews")