Fix frontend: remove Wails script tags, fix API mismatches, fix status bar

- Remove explicit /wails/ipc.js and /wails/runtime.js script tags from
  index.html (Wails v2 auto-injects its runtime, explicit tags cause 404s
  that block window.runtime and window.go from loading)
- Fix SecretStoreStatus() → IsSecretStoreInitialised() + IsSecretStoreUnlocked()
- Fix Connect() → ConnectSession()
- Fix QuickConnect(proto, host, port) → ConnectQuick(profileObject)
- Fix ImportProfilesDialog()/ExportProfilesDialog() → SelectFile/ExportProfiles/SaveFile
- Fix CloseSession() → DisconnectSession()
- Fix TestConnection() → show notification (method doesn't exist in backend)
- Fix SaveCapture() → SaveSessionCapture()
- Fix updateStatusBar() to use existing #status-connection, #status-session-count,
  and #status-vault spans instead of replacing the entire status bar innerHTML

frontend/index.html

@@ -186,10 +186,6 @@
     <!-- Notification toasts -->
     <div id="notifications" class="notifications-container"></div>
 
-    <!-- Wails runtime (injected by the Wails framework) -->
-    <script src="/wails/ipc.js"></script>
-    <script src="/wails/runtime.js"></script>
-
     <!-- Vendor libraries -->
     <script src="/src/js/lib/xterm.min.js"></script>
     <script src="/src/js/lib/xterm-addon-fit.min.js"></script>