perf(analytics): 5表 updated_at 窄索引——health MAX 消除全表扫(128MB buffer pool)

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

yunke-server/app/db/models.py

@@ -256,6 +256,9 @@ class Customer(Base):
             "owner_account_id",
             "friend_id",
         ),
+        # /api/analytics/health MAX(updated_at) 新鲜度探针;无索引时全表扫。
+        # 「模型+迁移双声明」防 alembic autogenerate 反 DROP(c3d4e5f6a7b8)。
+        Index("ix_customer_updated_at", "updated_at"),
     )
 
 
@@ -314,6 +317,8 @@ class ChatGroup(Base):
             "owner_account_id",
             "room_id",
         ),
+        # /api/analytics/health MAX(updated_at) 新鲜度探针(c3d4e5f6a7b8)。
+        Index("ix_chat_group_updated_at", "updated_at"),
     )
 
 
@@ -480,6 +485,9 @@ class Media(Base):
 
     __table_args__ = (
         Index("ix_media_type_channel", "media_type", "channel"),
+        # /api/analytics/health MAX(updated_at) 新鲜度探针——media 5 万宽行
+        # (多个 TEXT/JSON 列)在 128MB buffer pool 下最伤(c3d4e5f6a7b8)。
+        Index("ix_media_updated_at", "updated_at"),
     )
 
 
@@ -531,6 +539,8 @@ class PhoneCall(Base):
 
     __table_args__ = (
         Index("ix_phone_call_user_time", "user_id", "start_call_time"),
+        # /api/analytics/health MAX(updated_at) 新鲜度探针(c3d4e5f6a7b8)。
+        Index("ix_phone_call_updated_at", "updated_at"),
     )
 
 
@@ -649,6 +659,9 @@ class MomentsPost(Base):
     fetched_at: Mapped[dt.datetime] = _fetched_at()
     updated_at: Mapped[dt.datetime] = _updated_at()
 
+    # /api/analytics/health MAX(updated_at) 新鲜度探针(c3d4e5f6a7b8)。
+    __table_args__ = (Index("ix_moments_post_updated_at", "updated_at"),)
+
 
 # ===========================================================================
 # 5. Operational / bookkeeping tables (local; no raw_json/version)