feat(ECR-006): 落地运营后台 Phase A（admin API + admin-h5）

新增独立鉴权的 /api/v1/admin 与 Vue 控制台；会员授予与审计同事务，并补集成/单测。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/internal/service/admin/service_test.go

@@ -0,0 +1,16 @@
+package admin
+
+import "testing"
+
+func TestPlanDays(t *testing.T) {
+	cases := map[string]int{"month": 31, "quarter": 92, "year": 366}
+	for plan, want := range cases {
+		got, err := planDays(plan)
+		if err != nil || got != want {
+			t.Fatalf("planDays(%s)=%d,%v want %d", plan, got, err, want)
+		}
+	}
+	if _, err := planDays("week"); err == nil {
+		t.Fatal("expected invalid plan")
+	}
+}