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/ww_db/models.py

@@ -11,7 +11,10 @@ from typing import Any
 
 from sqlalchemy import (
     BigInteger,
+    CheckConstraint,
+    DateTime,
     ForeignKey,
+    Index,
     Integer,
     LargeBinary,
     Text,
@@ -37,7 +40,7 @@ class User(UuidPk, CreatedAt, Base):
 
 class Project(UuidPk, TimestampedMixin, Base):
     __tablename__ = "projects"
-    owner_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("users.id"), nullable=False)
+    owner_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("users.id"), nullable=False, index=True)
     title: Mapped[str] = mapped_column(Text, nullable=False)
     genre: Mapped[str | None] = mapped_column(Text)
     logline: Mapped[str | None] = mapped_column(Text)
@@ -92,6 +95,13 @@ class Outline(UuidPk, Base):
 
 class ChapterDigest(UuidPk, CreatedAt, Base):
     __tablename__ = "chapter_digests"
+    __table_args__ = (
+        Index(
+            "ix_chapter_digests_project_chapter",
+            "project_id",
+            text("chapter_no DESC"),
+        ),
+    )
     project_id: Mapped[uuid.UUID] = mapped_column(
         ForeignKey("projects.id", ondelete="CASCADE"), nullable=False, index=True
     )
@@ -101,7 +111,13 @@ class ChapterDigest(UuidPk, CreatedAt, Base):
 
 class Foreshadow(UuidPk, Base):
     __tablename__ = "foreshadow"
-    __table_args__ = (UniqueConstraint("project_id", "code"),)
+    __table_args__ = (
+        UniqueConstraint("project_id", "code"),
+        CheckConstraint(
+            "status IN ('OPEN', 'PARTIAL', 'CLOSED', 'OVERDUE')",
+            name="ck_foreshadow_status",
+        ),
+    )
     project_id: Mapped[uuid.UUID] = mapped_column(
         ForeignKey("projects.id", ondelete="CASCADE"), nullable=False, index=True
     )
@@ -116,7 +132,10 @@ class Foreshadow(UuidPk, Base):
     links: Mapped[list[Any]] = mapped_column(JSONB, server_default=text("'[]'"))
     progress: Mapped[list[Any]] = mapped_column(JSONB, server_default=text("'[]'"))
     updated_at: Mapped[datetime] = mapped_column(
-        nullable=False, server_default=text("now()"), onupdate=text("now()")
+        DateTime(timezone=True),
+        nullable=False,
+        server_default=text("now()"),
+        onupdate=text("now()"),
     )
 
 
@@ -132,8 +151,15 @@ class StyleFingerprint(UuidPk, CreatedAt, Base):
 
 class Rule(UuidPk, CreatedAt, Base):
     __tablename__ = "rules"
+    __table_args__ = (
+        Index(
+            "ix_rules_global",
+            "id",
+            postgresql_where=text("project_id IS NULL"),
+        ),
+    )
     project_id: Mapped[uuid.UUID | None] = mapped_column(
-        ForeignKey("projects.id", ondelete="CASCADE")
+        ForeignKey("projects.id", ondelete="CASCADE"), index=True
     )
     level: Mapped[str] = mapped_column(Text, nullable=False)
     content: Mapped[str] = mapped_column(Text, nullable=False)
@@ -141,7 +167,13 @@ class Rule(UuidPk, CreatedAt, Base):
 
 class Chapter(UuidPk, CreatedAt, Base):
     __tablename__ = "chapters"
-    __table_args__ = (UniqueConstraint("project_id", "chapter_no", "version"),)
+    __table_args__ = (
+        UniqueConstraint("project_id", "chapter_no", "version"),
+        CheckConstraint(
+            "status IN ('draft', 'accepted')",
+            name="ck_chapters_status",
+        ),
+    )
     project_id: Mapped[uuid.UUID] = mapped_column(
         ForeignKey("projects.id", ondelete="CASCADE"), nullable=False, index=True
     )
@@ -172,6 +204,14 @@ class ChapterInjection(UuidPk, TimestampedMixin, Base):
 
 class ChapterReview(UuidPk, CreatedAt, Base):
     __tablename__ = "chapter_reviews"
+    __table_args__ = (
+        Index(
+            "ix_chapter_reviews_project_chapter",
+            "project_id",
+            "chapter_no",
+            text("created_at DESC"),
+        ),
+    )
     project_id: Mapped[uuid.UUID] = mapped_column(
         ForeignKey("projects.id", ondelete="CASCADE"), nullable=False, index=True
     )
@@ -217,8 +257,8 @@ class TierRouting(UuidPk, Base):
 
 class UsageLedger(UuidPk, CreatedAt, Base):
     __tablename__ = "usage_ledger"
-    owner_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("users.id"), nullable=False)
-    project_id: Mapped[uuid.UUID | None] = mapped_column(ForeignKey("projects.id"))
+    owner_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("users.id"), nullable=False, index=True)
+    project_id: Mapped[uuid.UUID | None] = mapped_column(ForeignKey("projects.id"), index=True)
     provider: Mapped[str] = mapped_column(Text, nullable=False)
     model: Mapped[str] = mapped_column(Text, nullable=False)
     input_tokens: Mapped[int] = mapped_column(Integer, nullable=False)
@@ -246,6 +286,13 @@ class Skill(UuidPk, CreatedAt, Base):
 
 class Job(UuidPk, TimestampedMixin, Base):
     __tablename__ = "jobs"
+    __table_args__ = (
+        Index(
+            "ix_jobs_status_running",
+            "status",
+            postgresql_where=text("status = 'running'"),
+        ),
+    )
     project_id: Mapped[uuid.UUID | None] = mapped_column(
         ForeignKey("projects.id", ondelete="CASCADE")
     )