style(hermes): use dashboard icon and move MCP to toolbar end

Swap ExternalLink for LayoutDashboard on the Hermes Web UI button —
clicking it may launch `hermes dashboard` rather than just open a URL,
so a panel-style glyph reads truer than a generic external-link icon.
Also reorder the toolbar so MCP sits in the final slot, matching the
claude/codex/gemini/opencode layout.

src/App.tsx

@@ -26,7 +26,7 @@ import {
   KeyRound,
   Shield,
   Cpu,
-  ExternalLink,
+  LayoutDashboard,
 } from "lucide-react";
 import { getCurrentWindow } from "@tauri-apps/api/window";
 import type { Provider, VisibleApps } from "@/types";
@@ -1410,6 +1410,15 @@ function App() {
                               >
                                 <Brain className="w-4 h-4" />
                               </Button>
+                              <Button
+                                variant="ghost"
+                                size="sm"
+                                onClick={() => void openHermesWebUI()}
+                                className="text-muted-foreground hover:text-foreground hover:bg-black/5 dark:hover:bg-white/5 w-8 px-2"
+                                title={t("hermes.webui.open")}
+                              >
+                                <LayoutDashboard className="w-4 h-4" />
+                              </Button>
                               <Button
                                 variant="ghost"
                                 size="sm"
@@ -1419,15 +1428,6 @@ function App() {
                               >
                                 <McpIcon size={16} />
                               </Button>
-                              <Button
-                                variant="ghost"
-                                size="sm"
-                                onClick={() => void openHermesWebUI()}
-                                className="text-muted-foreground hover:text-foreground hover:bg-black/5 dark:hover:bg-white/5 w-8 px-2"
-                                title={t("hermes.webui.open")}
-                              >
-                                <ExternalLink className="w-4 h-4" />
-                              </Button>
                             </>
                           ) : activeApp === "openclaw" ? (
                             <>