feat(wallets): subtle empty-state hint in the fixed-height list

With the list now pinned at max height, a few wallets leave blank space below
the cards. Fill it — only when there's real room to spare — with a subtle
centered folder glyph + "Scan a folder to find more wallets" (OnSurfaceDisabled),
so the area reads as a gentle nudge toward the scan action rather than dead
space. Purely decorative (draw-list only, clipped to the list); the actions stay
below. New i18n key wallets_empty_hint, translated across all 8 languages.

Verified on the sweep: the hint centers in the gap and reads subtly on both dark
and light themes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/add_missing_translations.py

@@ -2244,6 +2244,16 @@ TRANSLATIONS = {
         "ru": "Больше не сканировать эту папку", "zh": "停止扫描此文件夹",
         "ja": "このフォルダーのスキャンを停止", "ko": "이 폴더 스캔 중지"
     },
+    "wallets_empty_hint": {
+        "es": "Escanea una carpeta para encontrar más carteras",
+        "de": "Ordner durchsuchen, um weitere Wallets zu finden",
+        "fr": "Analysez un dossier pour trouver d'autres portefeuilles",
+        "pt": "Verifique uma pasta para encontrar mais carteiras",
+        "ru": "Просканируйте папку, чтобы найти другие кошельки",
+        "zh": "扫描文件夹以查找更多钱包",
+        "ja": "フォルダーをスキャンして他のウォレットを探す",
+        "ko": "폴더를 스캔하여 다른 지갑 찾기"
+    },
 }
 
 def main():