Clear all auxiliary tab contents before applying a new grid orientation to prevent stale view reuse, and remove the delayed tab-index workaround. Also treat `ProfilesViewModel` as a transient view so its view is recreated like other dynamic tabs.
Add a `ConditionalWeakTable`-based view cache keyed by view model instance for `MsgViewModel`, `ClashProxiesViewModel`, and `ClashConnectionsViewModel` so repeated bindings reuse the same control. The locator now also handles missing registrations and null factory results more explicitly by returning descriptive `TextBlock` messages.