feat(admin): view a user's shard footprint at /admin/users/:id

Add a "View" action beside Edit in the users table that opens a dedicated,
read-only page showing everything the uo-link shard knows about a user,
scoped to their linked game accounts: character rosters, currently-online
characters, houses (IDOC-first), and recent vendor sales.

Backend (admin-only, under the existing /users adminOnly gate):
- GET /admin/users/:id — single sanitized user (page is deep-linkable)
- GET /admin/users/:id/shard/{accounts,sales,houses,online}
- shardState: listHousesByAccounts / listOnlineByAccounts (+ model shapers)
- Extract salesForAccounts into utils/shardSales; reuse in player getSales
- Live rosters reuse the existing admin-bypass /admin/shard/* endpoints,
  so no new routes for roster/vendors/char

Frontend:
- UserDetail page reusing CharacterStats / GameAccounts / VendorSales
- GameAccounts gains a readOnly prop (drops link form + self-voice copy)
- api.admin.getUser + api.admin.userShard(id) scope; route + layout title

Tests: adminUserShard.test.js (404, account scoping, empty accounts,
salesForAccounts cap/filter). Full server suite 164 pass; client builds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0114TpmrNW4wNXsHq5CR72jQ

server/src/model/shardState/shardState.model.js

@@ -136,9 +136,8 @@ async function upsertHouse(data) {
   await db.upsertHouse(data.serial, fields)
 }
 
-async function listIdoc() {
-  const rows = await db.listIdocHouses()
-  return rows.map((r) => ({
+function shapeHouse(r) {
+  return {
     serial: r.serial,
     stage: r.stage,
     map: r.map,
@@ -153,7 +152,24 @@ async function listIdoc() {
     lastRefreshed: r.last_refreshed,
     isIdoc: Boolean(r.is_idoc),
     updatedAt: r.updated_at,
-  }))
+  }
+}
+
+async function listIdoc() {
+  const rows = await db.listIdocHouses()
+  return rows.map(shapeHouse)
+}
+
+// Houses owned by the given game accounts (admin: a user's linked accounts).
+async function listHousesForAccounts(accounts) {
+  const rows = await db.listHousesByAccounts(accounts)
+  return rows.map(shapeHouse)
+}
+
+// Online players on the given game accounts (admin: a user's linked accounts).
+async function listOnlineForAccounts(accounts) {
+  const rows = await db.listOnlineByAccounts(accounts)
+  return rows.map(shapeOnline)
 }
 
 module.exports = {
@@ -163,9 +179,11 @@ module.exports = {
   onlineCount,
   listOnline,
   listOnlineLinked,
+  listOnlineForAccounts,
   addEconomySample,
   listEconomy,
   latestEconomy,
   upsertHouse,
   listIdoc,
+  listHousesForAccounts,
 }