fix(lite): "Open data folder" points to the actual lite wallet dir

The lite SilentDragonXLite backend stores its wallet in its own directory
(dirs::data_dir()/silentdragonxlite — %APPDATA%\silentdragonxlite on Windows,
~/.silentdragonxlite on Linux, ~/Library/Application Support/silentdragonxlite on
macOS), NOT the full-node getDragonXDataDir() (…/Hush/DRAGONX). The newly added
lite "Open data folder" button opened the wrong (full-node) directory.

Add Platform::getLiteWalletDataDir() mirroring the backend's get_zcash_data_path
for the "main" chain, and point the lite button at it. The full-node button is
unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/util/platform.h

@@ -61,6 +61,15 @@ public:
      * @return Path like ~/.hush/DRAGONX/ or %APPDATA%\Hush\DRAGONX\
      */
     static std::string getDataDir();
+
+    /**
+     * @brief Get the LITE wallet data directory (where the SilentDragonXLite backend stores
+     *        silentdragonxlite-wallet.dat). Mirrors the backend's get_zcash_data_path() for the
+     *        "main" chain: dirs::data_dir()/silentdragonxlite on Windows/macOS, ~/.silentdragonxlite
+     *        on Linux. Distinct from getDragonXDataDir() (the full-node blocks/wallet dir).
+     * @return Path like ~/.silentdragonxlite/ or %APPDATA%\silentdragonxlite\
+     */
+    static std::string getLiteWalletDataDir();
     
     /**
      * @brief Get the config directory for storing wallet exports/backups