chore(quality): resolve SonarQube code smells across website

Clears the 124 CODE_SMELL findings from the SonarQube scan (server, client,
and bot). All changes are behaviour-preserving refactors — no route, protocol,
schema, or config changes — verified against the full server (381) and client
(43) test suites plus a clean client build.

By rule:
- S3776 (20, cognitive complexity): extract helpers/handlers so each function
  drops under the threshold — shard model upsert builders, page/wiki update,
  block validation, notification stream mapping (dispatch table), SSO mobile
  login, shard ingest deps, uo-link socket backfill/connect, the bot slash-
  command dispatchers + discord manager, and the Shard/UserDetail/HeroEditor/
  CharacterStats React components.
- S4624 (34, nested template literals): pull inner templates into locals /
  a withQs() helper; rewrite shardEvents.describe() as a formatter table.
- S3358 (35, nested ternaries): lift to if/else vars, lookup maps, small
  components, or guarded JSX expressions.
- S6479 (12, array-index React keys): key by stable content instead of index
  (two in-editor lists left as-is; index matches their by-index edit model).
- S6353 (6): [0-9]/[^0-9] -> \d/\D.  S125 (5): reword state-shape comments that
  parsed as code.  S3800/S3782 (botScore): JSDoc-type PATH_WEIGHTS tuples.
- S6481 (2): memoize Auth/Site context values (and SiteContext brand).
- S4144: dedupe HeroEditor upload handler into useImageUpload().
- S1126 (2), S6035, S5869 (redundant A-Z under /i), S5843 (town-name regex ->
  prefix list): assorted one-liners.

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

client/src/contexts/SiteContext.jsx

@@ -1,4 +1,4 @@
-import { createContext, useContext, useEffect, useState, useCallback } from 'react'
+import { createContext, useContext, useEffect, useState, useCallback, useMemo } from 'react'
 import { api } from '../api/client.js'
 
 const SiteContext = createContext(null)
@@ -23,7 +23,7 @@ export function SiteProvider({ children }) {
     refresh()
   }, [refresh])
 
-  const brand = settings.brand || {}
+  const brand = useMemo(() => settings.brand || {}, [settings])
 
   // Apply the instance accent color to the CSS variable the theme is built on,
   // so branding flows to every `var(--accent)` at runtime (no rebuild).
@@ -31,17 +31,22 @@ export function SiteProvider({ children }) {
     if (brand.accent) document.documentElement.style.setProperty('--accent', brand.accent)
   }, [brand.accent])
 
-  const value = {
-    settings,
-    loading,
-    refresh,
-    brand,
-    mode: settings.site_mode || 'live',
-    siteTitle: brand.name || settings.site_title || 'Runic Gateway',
-    siteShortName: brand.shortName || brand.name || settings.site_title || 'Runic Gateway',
-    contactEmail: brand.contactEmail || settings.contact_email || '',
-    heroImage: brand.hero || '/assets/img/runic-emblem.png',
-  }
+  // Memoized so consumers don't re-render on every provider render (brand is a
+  // fresh object each render, which would otherwise churn the context value).
+  const value = useMemo(
+    () => ({
+      settings,
+      loading,
+      refresh,
+      brand,
+      mode: settings.site_mode || 'live',
+      siteTitle: brand.name || settings.site_title || 'Runic Gateway',
+      siteShortName: brand.shortName || brand.name || settings.site_title || 'Runic Gateway',
+      contactEmail: brand.contactEmail || settings.contact_email || '',
+      heroImage: brand.hero || '/assets/img/runic-emblem.png',
+    }),
+    [settings, loading, refresh, brand],
+  )
 
   return <SiteContext.Provider value={value}>{children}</SiteContext.Provider>
 }