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.

openspec/changes/archive/2026-09-25-add-membership-messaging/proposal.md

@@ -0,0 +1,30 @@
+## Why
+
+Members have no growth ladder and no reach-out channel: a customer's spending never converts into status, and order events (payment, dispatch, refund) are invisible unless the shopper re-opens the buyer center. tigshop's level page is itself a half-finished stub, so vmall defines its own member-level and growth-value design instead of porting that page, and pairs it with a system in-site message inbox so transaction events actually reach the customer.
+
+## What Changes
+
+- Add platform-managed member levels with bilingual name, icon, growth-value threshold, and bilingual benefits description.
+- Accrue growth value from an order's realized paid amount when the customer confirms receipt, recorded in an append-only growth ledger in the same style as the points ledger.
+- Automatically upgrade a customer's level inside the accrual transaction, writing `users.level` with a guarded update from the highest threshold the customer's growth qualifies for.
+- Emit system in-site messages on order payment, shipment dispatch, and refund completion events.
+- Give customers a message inbox with unread/read state, mark-all-read, soft deletion, and an unread count endpoint for the header badge.
+- Surface all of it through `@vmall/shared`: a Mall member-center level page, a message center, and a top-bar unread badge (with fixed-adapter fallback and live picks for the new domains), plus a member-level management page in the admin console.
+
+## Capabilities
+
+### New Capabilities
+- `membership`: Member level catalog, growth-value accrual ledger, automatic upgrade-only leveling, and level benefits display.
+- `messaging`: Order and after-sale event-driven system messages, per-user unread/read state with soft deletion, and unread counting.
+
+### Modified Capabilities
+- `frontend-mall`: Member-center level page, message center, and top-bar unread badge use the selected API adapter instead of absent or local state.
+- `frontend-admin`: Member level management beside the existing platform operations.
+
+## Non-goals
+
+Paid level purchases, level-exclusive pricing, SMS/email/WeChat-template push delivery, real-time WebSocket push (polling or fetch-on-entry is enough), and rich-text message bodies are excluded.
+
+## Impact
+
+Adds one Postgres migration, Rust `membership` and `messaging` modules with order/fulfillment event hooks, shared types and API methods, `membership` and `messaging` Mall domains with fixed adapters and live picks, Mall pages `user/membership` and `user/messages` plus the shell badge, and an admin `member-levels` page.