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/models/app_state.rs

@@ -79,6 +79,7 @@ pub struct AppState {
     pub results_selected_indices: std::collections::HashSet<usize>,
     pub results_filter_query: String,
     pub results_is_filtering: bool,
+    pub results_name_offset: usize,
 
     // Downloads
     pub downloads: Vec<DownloadEntry>,
@@ -154,6 +155,7 @@ impl AppState {
             results_selected_indices: std::collections::HashSet::new(),
             results_filter_query: String::new(),
             results_is_filtering: false,
+            results_name_offset: 0,
 
             downloads: Vec::new(),
             downloads_table_state,