feat: wave 2 migration (P3, P5, P7 openspec changes)

Implements, verifies, and archives the three remaining Wave 2 changes from
openspec/MIGRATION-PLAN.md.

- add-wallet-settlement (P3): demo recharge, guarded withdrawal freeze and
  one-time admin review, paginated own fund entries, idempotent per-shop
  weekly/monthly settlement statements with commission rate and one-time
  payout confirmation.
- add-merchant-onboarding (P5): personal/enterprise applications with one live
  application per user, guarded review with mandatory rejection reason, and
  transactional shop + owner provisioning returning one-time credentials;
  mall onboarding/status pages and an admin review console.
- add-membership-messaging (P7): platform member levels, append-only growth
  accrual on order completion with guarded one-way leveling, order/shipment/
  refund system messages with unread/read state and soft deletion, plus the
  mall header unread badge.

Backend: migrations 0019-0023, new wallet, settlement, merchant_onboarding,
membership and messaging modules, event hooks in order/fulfillment/aftersale,
and integration suites for each. Shared contract extended and all three
frontends updated; code indexes, domain docs, backend guidelines and the
migration tracker synced.

Verification: cargo test -p vmall-api green twice consecutively; mall, admin
and shop-admin builds pass; browser smoke on every new surface; openspec
validate --all --strict green (33 passed).

The three changes share the @vmall/shared contract, the mall mock adapter and
per-app locale/nav files, so they are committed together to keep every commit
buildable.

apps/mall/locales/membership.ts

@@ -0,0 +1,55 @@
+// Buyer membership center: level, growth total, progress and growth history.
+export default {
+  en: {
+    membership: {
+      title: "Membership",
+      entry: "My level",
+      loadFailed: "Unable to load your membership.",
+      currentLevel: "Current level",
+      benefits: "Level benefits",
+      growthTotal: "Growth total",
+      growthUnit: "growth",
+      noLevel: "No level yet",
+      noLevelHint: "Reach {threshold} {unit} to unlock {level}.",
+      topLevel: "Top level reached",
+      topLevelHint: "You are at the highest level — your benefits stay as they are.",
+      progressTitle: "Progress to {level}",
+      progressThreshold: "{current} / {threshold} {unit}",
+      remaining: "{remaining} {unit} to go",
+      historyTitle: "Growth history",
+      historyEmpty: "No growth entries yet.",
+      historyFailed: "Unable to load growth history.",
+      historyDate: "Time",
+      historyReason: "Reason",
+      historyDelta: "Growth",
+      historyTotal: "Total after",
+      reason_order_complete: "Order completed",
+    },
+  },
+  zh: {
+    membership: {
+      title: "会员中心",
+      entry: "我的等级",
+      loadFailed: "会员信息加载失败。",
+      currentLevel: "当前等级",
+      benefits: "等级权益",
+      growthTotal: "成长值",
+      growthUnit: "成长值",
+      noLevel: "暂无等级",
+      noLevelHint: "再获得 {threshold} {unit} 即可解锁 {level}。",
+      topLevel: "已是最高等级",
+      topLevelHint: "您已达到最高等级，权益保持不变。",
+      progressTitle: "距离 {level}",
+      progressThreshold: "{current} / {threshold} {unit}",
+      remaining: "还差 {remaining} {unit}",
+      historyTitle: "成长值明细",
+      historyEmpty: "暂无成长值记录。",
+      historyFailed: "成长值明细加载失败。",
+      historyDate: "时间",
+      historyReason: "原因",
+      historyDelta: "成长值",
+      historyTotal: "变动后累计",
+      reason_order_complete: "订单完成",
+    },
+  },
+};