feat(tui): scroll long result names and page through results

Closes #55.

While [2] Results is focused the Info pane describes the highlighted
result, so a truncated path can be read in full. h/l (or the arrow keys)
scroll the filename column by display cells, 0 and $ jump to either end
of the highlighted name, and Home/End, g/G, PgUp/PgDn and Ctrl-f/b/d/u
move through the list; the same keys work while a filter is being typed.

Ctrl chords are no longer read as their bare letter: outside [2] they do
nothing, where before Ctrl-d deleted a search and Ctrl-c opened rooms.
Space after a filter that matches nothing no longer indexes an empty
list.

soulseek-rs/src/ui/main_tui/browse.rs

@@ -192,13 +192,7 @@ impl MainTui {
 
     /// The username of the highlighted search result (filter-aware).
     pub(super) fn highlighted_result_owner(&self) -> Option<String> {
-        let selected = self.state.results_table_state.selected()?;
-        let items = if self.state.results_filter_query.is_empty() {
-            &self.state.results_items
-        } else {
-            &self.state.results_filtered_items
-        };
-        items.get(selected).map(|f| f.username.clone())
+        self.highlighted_result().map(|f| f.username.clone())
     }
 
     /// Drain browse responses into any loading tabs, or time them out.