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/store/sqlite_migrate_test.go

@@ -29,8 +29,8 @@ func TestSQLiteMigrateUpDown(t *testing.T) {
 	if dirty {
 		t.Fatalf("schema dirty after MigrateUp")
 	}
-	if v != 17 {
-		t.Errorf("version = %d, want 17", v)
+	if v != 18 {
+		t.Errorf("version = %d, want 18", v)
 	}
 
 	// 2. Core tables exist.
@@ -38,7 +38,7 @@ func TestSQLiteMigrateUpDown(t *testing.T) {
 		"users", "devices", "plans", "subscriptions", "code_batches", "codes",
 		"usage_daily", "audit_log", "providers", "nodes", "node_events",
 		"directory_version", "provision_idempotency", "replacements", "admins",
-		"connect_credentials", "usage_device_daily", "sessions", "usage_hourly",
+		"connect_credentials", "usage_device_daily", "sessions", "usage_hourly", "usage_device_hourly",
 	} {
 		var name string
 		err := db.QueryRow(

server/internal/store/usage_device_curve_test.go

@@ -0,0 +1,56 @@
+package store_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/wangjia/pangolin/server/internal/usage"
+)
+
+// Per-device curve (#10②): UsageCurve(deviceUUID) must return only that device's
+// data, account curve (deviceUUID="") the total, and a user must never read
+// another user's device (JOIN enforces ownership).
+func TestSQLite_UsageCurve_PerDevice(t *testing.T) {
+	ctx := context.Background()
+	db := openSQLite(t)
+	mustExec := func(q string, args ...any) {
+		if _, err := db.Exec(q, args...); err != nil {
+			t.Fatalf("seed %q: %v", q, err)
+		}
+	}
+	mustExec(`INSERT INTO users (id, uuid, email, pw_hash, dp_uuid, status) VALUES (1,'u1','u1@e','h','dp1','active'),(2,'u2','u2@e','h','dp2','active')`)
+	mustExec(`INSERT INTO devices (id, uuid, user_id, name, platform) VALUES (10,'devA',1,'A','macos'),(20,'devB',1,'B','ios'),(30,'devC',2,'C','windows')`)
+
+	h := time.Now().UTC().Unix()/3600 - 2 // 2h ago, within window
+	mustExec(`INSERT INTO usage_device_hourly (user_id, device_id, hour, bytes_up, bytes_down, minutes_used) VALUES (1,10,?,1000,2000,5),(1,20,?,300,400,2),(2,30,?,999,0,9)`, h, h, h)
+	mustExec(`INSERT INTO usage_hourly (user_id, hour, bytes_up, bytes_down, minutes_used) VALUES (1,?,1300,2400,7)`, h)
+
+	svc := usage.NewService(usage.NewStore(db), nil, nil, time.Hour)
+	sum := func(uid int64, dev string) (up, down uint64, mins int) {
+		pts, e := svc.UsageCurve(ctx, uid, 3, 0, dev)
+		if e != nil {
+			t.Fatalf("UsageCurve(dev=%q): %v", dev, e)
+		}
+		for _, p := range pts {
+			up += p.BytesUp
+			down += p.BytesDown
+			mins += p.MinutesUsed
+		}
+		return
+	}
+
+	if up, down, m := sum(1, "devA"); up != 1000 || down != 2000 || m != 5 {
+		t.Errorf("devA curve = %d/%d/%d, want 1000/2000/5", up, down, m)
+	}
+	if up, _, _ := sum(1, "devB"); up != 300 {
+		t.Errorf("devB curve up = %d, want 300", up)
+	}
+	if up, _, _ := sum(1, ""); up != 1300 {
+		t.Errorf("account curve up = %d, want 1300", up)
+	}
+	// user 1 querying user 2's device → empty (ownership via JOIN).
+	if up, _, _ := sum(1, "devC"); up != 0 {
+		t.Errorf("cross-user leak: devC visible to user1, up=%d", up)
+	}
+}

server/internal/store/usage_tz_test.go

@@ -37,7 +37,7 @@ func TestSQLite_UsageCurve_LocalDayBucketing(t *testing.T) {
 	svc := usage.NewService(usage.NewStore(db), nil, nil, time.Hour)
 
 	find := func(days, offset int, date string) (usage.UsagePoint, bool) {
-		pts, e := svc.UsageCurve(ctx, 1, days, offset)
+		pts, e := svc.UsageCurve(ctx, 1, days, offset, "")
 		if e != nil {
 			t.Fatalf("UsageCurve(off=%d): %v", offset, e)
 		}