feat(i18n): localize Voices tab (table header, search, inspector)

VoicesTab now translates the "Voices" title, search placeholder,
"New Voice" button, all six table column headers (Name, Language,
Generations, Samples, Effects, Channels), the avatar alt text, and
the per-row channel MultiSelect (placeholder + "(Default)" suffix).

VoiceInspector routes its form labels through the existing
`profileForm.fields.*` keys, has its own "Default Effects" hint and
avatar/save toasts, and reuses the ProfileForm Zod validation.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

app/src/i18n/locales/en/translation.json

@@ -21,6 +21,35 @@
     "settings": "Settings",
     "updateBadge": "Update"
   },
+  "voicesTab": {
+    "title": "Voices",
+    "loading": "Loading voices…",
+    "searchPlaceholder": "Search voices…",
+    "newVoice": "New Voice",
+    "avatarAlt": "{{name}} avatar",
+    "selectChannels": "Select channels…",
+    "channelDefaultLabel": "{{name}} (Default)",
+    "columns": {
+      "name": "Name",
+      "language": "Language",
+      "generations": "Generations",
+      "samples": "Samples",
+      "effects": "Effects",
+      "channels": "Channels"
+    }
+  },
+  "voiceInspector": {
+    "loading": "Loading…",
+    "defaultEffectsHint": "Applied automatically to new generations with this voice.",
+    "fields": {
+      "description": "Description"
+    },
+    "toast": {
+      "invalidImageFormat": "Please select PNG, JPG, or WebP",
+      "avatarUpdated": "Avatar updated",
+      "savedDescription": "\"{{name}}\" saved."
+    }
+  },
   "audioChannels": {
     "title": "Audio Channels",
     "newChannel": "New Channel",