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/components/HeroElement.jsx

@@ -34,14 +34,15 @@ function TextBlock({ props }) {
   const align = props.align || 'center'
   return (
     <div style={{ textAlign: align, textShadow: '0 2px 22px rgba(0,0,0,0.82)' }}>
-      {(props.lines || []).map((line, i) => {
+      {(props.lines || []).map((line) => {
         const Tag = /^(h1|h2|h3|p|span|div)$/.test(line.tag) ? line.tag : 'p'
+        const key = `${line.tag}:${(line.text || '').slice(0, 40)}`
         // A rich-text line (e.g. the homepage teaser) carries sanitized HTML;
         // sanitize again on render as defense in depth. Others render as text.
         if (line.html) {
           return (
             <Tag
-              key={i}
+              key={key}
               className="hero-rich"
               style={lineStyle(line)}
               dangerouslySetInnerHTML={{ __html: DOMPurify.sanitize(line.text || '') }}
@@ -49,7 +50,7 @@ function TextBlock({ props }) {
           )
         }
         return (
-          <Tag key={i} style={lineStyle(line)}>
+          <Tag key={key} style={lineStyle(line)}>
             {line.text}
           </Tag>
         )
@@ -59,11 +60,11 @@ function TextBlock({ props }) {
 }
 
 function Buttons({ props }) {
-  const justify = props.align === 'left' ? 'flex-start' : props.align === 'right' ? 'flex-end' : 'center'
+  const justify = { left: 'flex-start', right: 'flex-end' }[props.align] || 'center'
   return (
     <div style={{ display: 'flex', flexWrap: 'wrap', gap: props.gap ?? 12, justifyContent: justify }}>
-      {(props.items || []).map((b, i) => (
-        <Link key={i} to={b.to || '#'} className={`btn ${b.variant === 'ghost' ? 'btn-ghost' : 'btn-primary'}`}>
+      {(props.items || []).map((b) => (
+        <Link key={`${b.to || ''}:${b.label || ''}`} to={b.to || '#'} className={`btn ${b.variant === 'ghost' ? 'btn-ghost' : 'btn-primary'}`}>
           {b.label}
         </Link>
       ))}
@@ -160,12 +161,7 @@ export default function HeroElement({
   children,
 }) {
   const anchor = element.anchor || 'center'
-  const transform =
-    anchor === 'center'
-      ? 'translate(-50%, -50%)'
-      : anchor === 'top-right'
-        ? 'translateX(-100%)'
-        : undefined
+  const transform = { center: 'translate(-50%, -50%)', 'top-right': 'translateX(-100%)' }[anchor]
   // text_block/buttons may set a box width (px); kept within the containing block
   // (the hero section live, or the editor canvas) with small side gutters.
   const boxWidth =