feat(client): the whole client half (phase 3, slice 3)

The 35 files behind twelve public pages, seven admin views, two player views
and three core-page extensions, ported onto `window.__rg`. Every one of them
imports exactly the seven kit members plus `lib/format.js`, which is the
finding §2.7.1 predicted and this confirms.

`client/src/core.js` is the port mechanism, and unlike the server's it is a
plain read: `window.__rg` is published before any module chunk evaluates, so
there is no gap to defer around and a ported component keeps its ordinary
import shape. `client/src/api.js` rebuilds the UO namespaces over the request
primitive — same URLs, because §1.2 freezes the API surface.

SPA paths changed and API paths did not. `/site/shard` is `/uo/shard`, and the
admin paths lost their now-redundant `shard-` prefixes (`/admin/uo/ops`), a
clean break being the only moment that is free.

`shim/rg.js` becomes the single reader of the global, so the "core did not
publish its dependencies" message is reachable from whichever module the
bundler happens to touch first rather than from whichever one is imported
first — a guarantee that used to last until someone sorted the imports.

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

server/router/player/shard.controller.js

@@ -11,7 +11,8 @@ const uoLinkClient = require('../../utils/uoLinkClient')
 const shardLinks = require('../../model/shardLinks/shardLinks.model')
 const shardState = require('../../model/shardState/shardState.model')
 const shardClilocs = require('../../model/shardClilocs/shardClilocs.model')
-const { settings, activity } = require('../../core')
+const { activity } = require('../../core')
+const gameSignup = require('../../utils/gameSignup')
 const { salesForAccounts } = require('../../utils/shardSales')
 
 const log = require('../../core').logger('player-shard')
@@ -246,7 +247,7 @@ function mapCreateAccountError(res, result) {
 async function createGameAccount(req, res) {
   const { account, password } = req.body
   try {
-    if (!(await settings.isGameAccountSignupEnabled())) {
+    if (!(await gameSignup.isEnabled())) {
       return res.status(403).json({ message: 'Game-account signup is not available right now.' })
     }
     const result = await uoLinkClient.createAccount({