Cockpit poll refresh destroys open forms

## Problem
The 60-second `setInterval` poll calls render functions that rebuild the DOM via `innerHTML`. Any text the user typed in an open form is lost.

## Fix
Guard pattern — skip poll refresh when a form is active:

```js
if (activeTab === 'wants' && document.getElementById('want-form')?.style.display !== 'none') return;
```

Apply to all tabs with input forms.