Feat: Add theme folder access functionality in UI

preload.js

@@ -19,6 +19,7 @@ contextBridge.exposeInMainWorld("topbarAPI", {
   openDevTools: () => ipcRenderer.send("open-devtools"),
   openLogs: () => ipcRenderer.send("open-logs"),
   openWebsite: () => ipcRenderer.send("open-website"),
+  openTheme: () => ipcRenderer.send("open-theme"),
   openWiki: () => ipcRenderer.send("open-wiki"),
   openConfig: () => ipcRenderer.send("open-config")
 });