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/GameAccounts.jsx

@@ -121,7 +121,8 @@ function UnlinkButton({ account, onUnlink }) {
     try {
       await onUnlink(account)
     } catch (err) {
-      setError(err.status === 403 ? 'Protected account — refused.' : err.status === 404 ? 'Not linked.' : (err.message || 'Could not unlink.'))
+      const byStatus = { 403: 'Protected account — refused.', 404: 'Not linked.' }
+      setError(byStatus[err.status] || err.message || 'Could not unlink.')
       setBusy(false)
     }
   }