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/src/js/tabs.js

@@ -128,7 +128,7 @@ export class TabManager {
         }
 
         try {
-            await window.go.api.Service.CloseSession(sessionId);
+            await window.go.api.Service.DisconnectSession(sessionId);
         } catch (_) {
             // Session may already be closed — carry on
         }