Hide search input until search is rebuilt on the SDK
The current SearchResults filters useDocumentsStore.items, which only
contains the currently-loaded directory's entries. Full-tree and inbox
search were stripped in the WASM security-boundary migration and have
not been reinstated, so the feature ships half-working. Drop the search
inputs from TopBar and Sidebar until a proper SDK-backed search lands.
Route, component, store, and hook are retained — un-hiding is a
three-line revert to these two files.