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/sidebar/components/voice-package-card.module.css

@@ -0,0 +1,104 @@
+/* 双层 background 实现 pink → orange 渐变描边 */
+.card {
+  background:
+    linear-gradient(#ffffff, #ffffff) padding-box,
+    linear-gradient(
+      135deg,
+      var(--color-voice-gradient-start, #ff6fa3),
+      var(--color-voice-gradient-end, #ff9a5a)
+    ) border-box;
+  border: var(--border-card, 1.5px) solid transparent;
+  border-radius: var(--radius-xl, 16px);
+  box-shadow: var(--shadow-card, 0 1px 3px rgba(0, 0, 0, 0.04));
+  width: 100%;
+  box-sizing: border-box;
+  overflow: hidden;
+}
+
+.header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--spacing-md, 12px);
+  padding: var(--spacing-lg, 16px) var(--spacing-lg, 16px) var(--spacing-sm, 8px);
+}
+
+.title {
+  margin: 0;
+  font-size: var(--font-size-lg, 16px);
+  font-weight: 700;
+  color: var(--color-accent, #f84d96);
+  line-height: 1.3;
+}
+
+.micIcon {
+  flex: 0 0 auto;
+  width: 60px;
+  height: 60px;
+  border-radius: 50%;
+  background: linear-gradient(
+    135deg,
+    var(--color-voice-gradient-start, #ff6fa3),
+    var(--color-voice-gradient-end, #ff9a5a)
+  );
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  color: #ffffff;
+  box-shadow: 0 4px 12px rgba(255, 111, 163, 0.25);
+}
+
+.micGlyph {
+  color: inherit;
+}
+
+.usage {
+  margin: 0;
+  padding: 0 var(--spacing-lg, 16px);
+  font-size: var(--font-size-md, 14px);
+  color: var(--color-text-secondary, #9e9e9e);
+  line-height: 1.4;
+}
+
+.usageNumber {
+  color: var(--color-accent, #f84d96);
+  font-weight: 700;
+}
+
+.usageText {
+  color: var(--color-text-secondary, #9e9e9e);
+  font-weight: 400;
+}
+
+.footer {
+  padding: var(--spacing-md, 12px) var(--spacing-lg, 16px) var(--spacing-lg, 16px);
+}
+
+.buyBtn {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: var(--spacing-md, 12px) var(--spacing-lg, 16px);
+  border-radius: var(--radius-full, 999px);
+  background: linear-gradient(
+    90deg,
+    var(--color-button-gradient-start, #ff67e0),
+    var(--color-button-gradient-end, #ff52a2)
+  );
+  color: var(--color-text-primary, #ffffff);
+  font-size: var(--font-size-md, 14px);
+  font-weight: 600;
+  border: 0;
+  cursor: pointer;
+  width: 100%;
+  box-sizing: border-box;
+}
+
+.buyBtn:hover {
+  opacity: 0.9;
+}
+
+.buyBtn:focus-visible {
+  outline: 2px solid var(--color-accent, #f84d96);
+  outline-offset: 2px;
+}