feat(stats): #10 第②层 —— 统计页按设备过滤(per-device 本地日曲线)

镜像账户级时区曲线到「按设备」:
- migration 000018 `usage_device_hourly`(每设备 UTC 小时桶,稀疏)。
- ReportUsage deviceID>0 时加 AccumulateDeviceHourly;NodeStore 接口+impl+mock。
- usage.Store.DeviceHourlyRange(JOIN devices 校验归属+解析 uuid→id);UsageCurve
  增 deviceUUID 形参:空=账户级,非空=该设备本地日曲线(分桶逻辑复用)。
- /v1/usage?device=<uuid>;客户端 account_api.usage(device)、usageProvider key 改
  记录 (days,device)、stats_page 接 statsDeviceProvider → 选设备即重取该设备曲线。
测试:per-device 曲线隔离+归属校验(A的设备不进B)、UsageCurve(deviceUUID)、
migration v18、客户端 widget(选设备→/v1/usage 带 device=)。全量 go/flutter 绿。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/internal/usage/handler.go

@@ -67,7 +67,10 @@ func (h *UsageHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	points, apiErr := h.svc.UsageCurve(r.Context(), userID, days, offsetMin)
+	// device (UUID, optional): when set, return that device's curve only (#10②).
+	deviceUUID := r.URL.Query().Get("device")
+
+	points, apiErr := h.svc.UsageCurve(r.Context(), userID, days, offsetMin, deviceUUID)
 	if apiErr != nil {
 		apierr.WriteJSON(w, http.StatusInternalServerError, apiErr)
 		return

server/internal/usage/service.go

@@ -53,7 +53,8 @@ type UsagePoint struct {
 // It reads UTC hourly buckets (usage_hourly) and re-aggregates by local calendar
 // day, so "today" matches the user's local date regardless of server timezone
 // (fixes "29号却显示28号数据"). offsetMin out of ±14h falls back to 0 (UTC).
-func (svc *Service) UsageCurve(ctx context.Context, userID int64, days, offsetMin int) ([]UsagePoint, *apierr.Error) {
+// deviceUUID == "" → account-level curve; non-empty → that device's curve only.
+func (svc *Service) UsageCurve(ctx context.Context, userID int64, days, offsetMin int, deviceUUID string) ([]UsagePoint, *apierr.Error) {
 	if days < 1 {
 		days = 7
 	}
@@ -73,7 +74,13 @@ func (svc *Service) UsageCurve(ctx context.Context, userID int64, days, offsetMi
 	fromHour := fromLocal.UTC().Unix() / 3600
 	toHour := now.Unix() / 3600
 
-	rows, err := svc.store.HourlyRange(ctx, userID, fromHour, toHour)
+	var rows []HourBucket
+	var err error
+	if deviceUUID == "" {
+		rows, err = svc.store.HourlyRange(ctx, userID, fromHour, toHour)
+	} else {
+		rows, err = svc.store.DeviceHourlyRange(ctx, userID, deviceUUID, fromHour, toHour)
+	}
 	if err != nil {
 		return nil, apierr.ErrInternal
 	}

server/internal/usage/store.go

@@ -139,6 +139,33 @@ func (s *Store) HourlyRange(ctx context.Context, userID, fromHour, toHour int64)
 	return out, rows.Err()
 }
 
+// DeviceHourlyRange returns one device's UTC hourly buckets (usage_device_hourly)
+// for hour in [fromHour, toHour], oldest first. The JOIN both resolves the
+// client-facing device UUID to its internal id and enforces ownership (user_id),
+// so a user can never read another user's device curve.
+func (s *Store) DeviceHourlyRange(ctx context.Context, userID int64, deviceUUID string, fromHour, toHour int64) ([]HourBucket, error) {
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT uh.hour, uh.bytes_up, uh.bytes_down, uh.minutes_used
+		 FROM usage_device_hourly uh
+		 JOIN devices d ON d.id = uh.device_id
+		 WHERE d.user_id = ? AND d.uuid = ? AND uh.hour BETWEEN ? AND ?
+		 ORDER BY uh.hour ASC`,
+		userID, deviceUUID, fromHour, toHour)
+	if err != nil {
+		return nil, fmt.Errorf("store.DeviceHourlyRange: %w", err)
+	}
+	defer rows.Close()
+	var out []HourBucket
+	for rows.Next() {
+		var b HourBucket
+		if err := rows.Scan(&b.Hour, &b.BytesUp, &b.BytesDown, &b.MinutesUsed); err != nil {
+			return nil, fmt.Errorf("store.DeviceHourlyRange scan: %w", err)
+		}
+		out = append(out, b)
+	}
+	return out, rows.Err()
+}
+
 // DeviceUsageRow is one device's aggregated usage over a date window, joined to
 // the devices table for display metadata.  It is the per-device ("下分设备")
 // counterpart of DailyUsage's account rollup.

server/internal/usage/usage_integration_test.go

@@ -110,6 +110,14 @@ func applySchema(db *sql.DB) error {
 			ad_unlocked_at DATETIME(6) NULL,
 			PRIMARY KEY (user_id, date)
 		) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`,
+		`CREATE TABLE IF NOT EXISTS usage_hourly (
+			user_id      BIGINT UNSIGNED NOT NULL,
+			hour         BIGINT NOT NULL,
+			bytes_up     BIGINT UNSIGNED NOT NULL DEFAULT 0,
+			bytes_down   BIGINT UNSIGNED NOT NULL DEFAULT 0,
+			minutes_used INT NOT NULL DEFAULT 0,
+			PRIMARY KEY (user_id, hour)
+		) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`,
 		`INSERT IGNORE INTO plans (code, max_devices, daily_minutes, ad_gate)
 		 VALUES ('free',1,10,TRUE), ('pro',5,NULL,FALSE), ('team',10,NULL,FALSE)`,
 	}
@@ -445,7 +453,7 @@ func TestIntUsageCurveZeroFill(t *testing.T) {
 	db.Exec(`INSERT INTO usage_hourly (user_id, hour, bytes_up, bytes_down, minutes_used) VALUES (?,?,?,?,?)`,
 		uid, epochHour(today.AddDate(0, 0, -3)), 50, 60, 2)
 
-	points, apiErr := svc.UsageCurve(context.Background(), uid, 7, 0)
+	points, apiErr := svc.UsageCurve(context.Background(), uid, 7, 0, "")
 	if apiErr != nil {
 		t.Fatalf("curve: %v", apiErr)
 	}
@@ -486,7 +494,7 @@ func TestIntUsageCurveOnlyCurrentUser(t *testing.T) {
 	db.Exec(`INSERT INTO usage_hourly (user_id, hour, bytes_up, bytes_down, minutes_used) VALUES (?,?,?,?,?)`, uA, h, 111, 0, 1)
 	db.Exec(`INSERT INTO usage_hourly (user_id, hour, bytes_up, bytes_down, minutes_used) VALUES (?,?,?,?,?)`, uB, h, 999, 0, 9)
 
-	points, _ := svc.UsageCurve(context.Background(), uA, 1, 0)
+	points, _ := svc.UsageCurve(context.Background(), uA, 1, 0, "")
 	if len(points) != 1 || points[0].BytesUp != 111 {
 		t.Errorf("user A curve leaked other user data: %+v", points)
 	}