feat(audio): add downloadable extra Piper voices with accents

Adds Alma (sv), Alan, Northern English, Cori, Alba (British/Scottish)
and Joe, John, Norman (American) as optional voices downloaded one at
a time from Settings, with gender (measured pitch) and accent shown in
the voice lists. The standard install is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rc-racecore",
-  "version": "1.28.0",
+  "version": "1.29.0",
   "private": true,
   "description": "RC RaceCore live timing and race control with AMMC ingest and SQLite persistence",
   "engines": {