feat(tui): show the clear-all key in the searches pane's shortcuts

C has cleared every search for a while, and the keys popup says so, but
the pane's own shortcut bar never mentioned it, so it read as if d on
each search were the only way. The bar now lists it next to d → remove.

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

@@ -1810,6 +1810,14 @@ mod tests {
         assert_eq!(bar_rows, 1, "{wide}");
     }
 
+    #[test]
+    fn the_searches_pane_lists_its_clear_all_key() {
+        let mut tui = furnished_tui();
+        tui.state.focused_pane = FocusedPane::Searches;
+        let screen = screen_sized(&mut tui, 300, 40);
+        assert!(screen.contains("[C → clear all]"), "{screen}");
+    }
+
     #[test]
     fn page_keys_work_in_the_transfers_and_searches_lists_too() {
         let mut tui = furnished_tui();

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

@@ -594,6 +594,7 @@ impl MainTui {
                     ("s", "search"),
                     ("Enter", "results"),
                     ("d", "remove"),
+                    ("C", "clear all"),
                     ("m", "message"),
                     ("i", "inbox"),
                     ("c", "chat"),