fix: tab layout, clear search state, and cleanup

UI: remove trackertable from the Search tab and reorder widgets to correct layout. Tab helper: add QLayout directly instead of wrapping it in a temporary QWidget to avoid extra nesting. Search helper: clear the trackertable rows and reset state.posts when starting a new search to ensure fresh results. Minor: import check_space in main and simplify an unused loop variable in libtorrent_int for clarity/linting.

src/interface/utils/tabhelper.py

@@ -10,9 +10,7 @@ def create_tab(title, items, tabs, stretch):
             continue
 
         if isinstance(item, QLayout):
-            wrapper = QWidget()
-            wrapper.setLayout(item)
-            layout.addWidget(wrapper)
+            layout.addLayout(item)
         else:
             layout.addWidget(item)