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/routes/admin/views/PageBuilder.jsx

@@ -252,6 +252,9 @@ export default function PageBuilder() {
 
   const published = form.status === 'published'
 
+  let saveLabel = isEdit ? 'Save' : 'Create'
+  if (busy) saveLabel = 'Saving…'
+
   return (
     <section>
       {/* Toolbar */}
@@ -268,7 +271,7 @@ export default function PageBuilder() {
           </button>
         )}
         <button className="btn btn-primary btn-sq" onClick={() => save()} disabled={busy}>
-          {busy ? 'Saving…' : isEdit ? 'Save' : 'Create'}
+          {saveLabel}
         </button>
       </div>
 
@@ -277,7 +280,7 @@ export default function PageBuilder() {
           {error}
           {details.length > 0 && (
             <ul style={{ margin: '6px 0 0', paddingLeft: 18 }}>
-              {details.map((d, i) => <li key={i}>{d}</li>)}
+              {details.map((d) => <li key={d}>{d}</li>)}
             </ul>
           )}
         </div>
@@ -386,7 +389,7 @@ export default function PageBuilder() {
                 <span className="sans" style={{ color: 'var(--muted)', fontSize: '0.9rem' }}>Show in navigation</span>
               </label>
               <SelectField label="Nav group" value={form.settings.navGroup} onChange={setSetting('navGroup')} options={NAV_GROUPS} />
-              <TextField label="Nav order" value={form.settings.navOrder ?? ''} onChange={(v) => setSetting('navOrder')(v === '' ? null : v.replace(/[^0-9]/g, ''))} hint="Lower numbers appear first." />
+              <TextField label="Nav order" value={form.settings.navOrder ?? ''} onChange={(v) => setSetting('navOrder')(v === '' ? null : v.replace(/\D/g, ''))} hint="Lower numbers appear first." />
             </div>
           </div>