feat(platform): 首页门面三统计 + 运营后台展示模式配置

- 新表 platform_stat_display:每个指标可选 real/manual/random 三种
  展示模式,含建表 + anchor_minutes 两个 alembic migration
- 公开接口 GET /api/v1/platform/stats(无鉴权门面数字,登录前可读)
- 运营后台 GET/PATCH /admin/api/dashboard-display 配置展示模式
- 配套 model/repository/schema,注册 router(app/main+admin/main),
  导出 model,补 docs(api/database 索引及 3 篇详情)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/admin/main.py

@@ -18,6 +18,7 @@ from app.admin.routers.audit import router as audit_router
 from app.admin.routers.auth import router as auth_router
 from app.admin.routers.config import router as config_router
 from app.admin.routers.dashboard import router as dashboard_router
+from app.admin.routers.dashboard_display import router as dashboard_display_router
 from app.admin.routers.feedback import router as feedback_router
 from app.admin.routers.users import router as users_router
 from app.admin.routers.wallet import router as wallet_router
@@ -73,6 +74,7 @@ def health() -> dict[str, str]:
 
 admin_app.include_router(auth_router)
 admin_app.include_router(dashboard_router)
+admin_app.include_router(dashboard_display_router)
 admin_app.include_router(users_router)
 admin_app.include_router(wallet_router)
 admin_app.include_router(withdraw_router)

app/admin/routers/dashboard_display.py

@@ -0,0 +1,69 @@
+"""admin 首页三统计展示配置:列出三指标配置(+ 真实值预览)+ 改某指标(带审计 + 校验)。
+
+每指标可独立选 real/manual/random。计算逻辑见 app/repositories/platform_stat.py。
+权限:operator 可改(运营调门面数字),super 恒可。
+"""
+from __future__ import annotations
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, Request
+
+from app.admin.audit import write_audit
+from app.admin.deps import AdminDb, get_client_ip, get_current_admin, require_role
+from app.admin.schemas.dashboard_display import (
+    PlatformStatItemOut,
+    PlatformStatUpdateRequest,
+)
+from app.models.admin import AdminUser
+from app.repositories import platform_stat
+
+router = APIRouter(
+    prefix="/admin/api/dashboard-display",
+    tags=["admin-dashboard-display"],
+    dependencies=[Depends(get_current_admin)],
+)
+
+
+@router.get("", response_model=list[PlatformStatItemOut], summary="首页三统计配置 + 真实值预览")
+def list_display(db: AdminDb) -> list[PlatformStatItemOut]:
+    return [PlatformStatItemOut(**item) for item in platform_stat.get_config(db)]
+
+
+@router.patch(
+    "/{metric}", response_model=PlatformStatItemOut, summary="改某指标展示配置(带审计)"
+)
+def update_display(
+    metric: str,
+    body: PlatformStatUpdateRequest,
+    request: Request,
+    admin: Annotated[AdminUser, Depends(require_role("operator"))],
+    db: AdminDb,
+) -> PlatformStatItemOut:
+    try:
+        before, after = platform_stat.update_config(
+            db,
+            metric,
+            mode=body.mode,
+            manual_value=body.manual_value,
+            random_mult_min=body.random_mult_min,
+            random_mult_max=body.random_mult_max,
+            random_tick_seconds=body.random_tick_seconds,
+            random_anchor_minutes=body.random_anchor_minutes,
+            random_initial=body.random_initial,
+            apply_now=body.apply_now,
+            admin_id=admin.id,
+            commit=False,
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e)) from e
+
+    write_audit(
+        db, admin, action="dashboard_display.set", target_type="platform_stat",
+        target_id=metric, detail={"before": before, "after": after},
+        ip=get_client_ip(request), commit=False,
+    )
+    db.commit()
+
+    item = next(it for it in platform_stat.get_config(db) if it["metric"] == metric)
+    return PlatformStatItemOut(**item)

app/admin/schemas/dashboard_display.py

@@ -0,0 +1,38 @@
+"""admin 首页三统计展示配置 schemas。
+
+倍率用千分比整数(1.000→1000);total_saved 的 manual_value / random_current 单位是分。
+"""
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+
+class PlatformStatItemOut(BaseModel):
+    metric: str  # help_users / total_compares / total_saved
+    label: str  # 帮助用户 / 完成比价 / 累计节省
+    unit: str  # 人 / 次 / 分
+    mode: str  # real / manual / random
+    manual_value: int | None = None
+    random_mult_min: int
+    random_mult_max: int
+    random_tick_seconds: int
+    random_anchor_minutes: int
+    random_current: int | None = None
+    random_last_tick_at: str | None = None
+    real_value: int  # 当前真实值(给运营对比参考)
+    updated_at: str | None = None
+
+
+class PlatformStatUpdateRequest(BaseModel):
+    """改某指标配置(均可选,只改传了的字段)。"""
+
+    mode: str | None = None
+    manual_value: int | None = None
+    random_mult_min: int | None = None
+    random_mult_max: int | None = None
+    random_tick_seconds: int | None = None
+    random_anchor_minutes: int | None = None
+    # 切 random 时的初始基数;不传则用当前真实值播种
+    random_initial: int | None = None
+    # 立即更新:不等更新钟点,保存后马上把展示值刷新一次(real 快照/manual 生效/random ×一档)
+    apply_now: bool = False