feat(sidebar): redesign sidebar UI with three user states (light theme)

Replace the dark sidebar theme with a light-themed three-state UI
matching the design references:

- guest  : pink "login" pill in user row, no status pill on VIP card,
           "Activate VIP Membership" button shown
- member : "VIP membership not activated" subtitle, no status pill,
           "Activate VIP Membership" button shown
- vip    : pink "VIP Member" pill with diamond icon, "Activated" pill
           in VIP card header, no Activate button

Decompose into BackBar, UserHeader, VipBenefitsCard, and VoicePackageCard
under src/app/sidebar/components/. Delete obsolete GuestPanel,
UserInfoCard, and VipCta.

Lift VIP_BENEFITS to a shared src/data/constants/vip-benefits.ts so the
sidebar and subscription page render identical benefit copy.

Add five sidebar tokens (--color-card-surface, --color-voice-gradient-*
--border-card, --shadow-card, --color-pill-bg) to src/tokens/colors.css.

Includes barrelsby regeneration for src/app/sidebar/components and
side-effect barrel updates under src/stores/{auth,chat,sidebar,user},
plus package-lock.json from npm install (required for lint/typecheck).

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

src/app/subscription/components/subscription-screen.tsx

@@ -23,6 +23,7 @@ import {
   SUBSCRIPTION_PLANS,
   type SubscriptionPlanId,
 } from "@/data/constants/subscription-plans";
+import { VIP_BENEFITS } from "@/data/constants/vip-benefits";
 import { useUserState } from "@/stores/user/user-context";
 
 import { SubscriptionBackLink } from "./subscription-back-link";
@@ -34,13 +35,6 @@ import { SubscriptionPlanCard } from "./subscription-plan-card";
 import { SubscriptionUserRow } from "./subscription-user-row";
 import styles from "./subscription-screen.module.css";
 
-const VIP_BENEFITS = [
-  "Unlimited chat sessions per day",
-  "Unlimited free access to private messages",
-  "Unlimited access to AI boyfriend photos",
-  "Free voice chat for X minutes",
-] as const;
-
 const FALLBACK_USERNAME = "User name";
 
 export function SubscriptionScreen() {