feat(tui): configurable prefix character (#2157)

* feat(tui): configurable prefix character

* string not char because toml/json lol

Author: ellie

crates/atuin-client/src/settings.rs

@@ -330,6 +330,7 @@ pub struct Sync {
 #[derive(Clone, Debug, Deserialize, Default, Serialize)]
 pub struct Keys {
     pub scroll_exits: bool,
+    pub prefix: String,
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize)]
@@ -715,6 +716,7 @@ impl Settings {
             .set_default("enter_accept", false)?
             .set_default("sync.records", false)?
             .set_default("keys.scroll_exits", true)?
+            .set_default("keys.prefix", "a")?
             .set_default("keymap_mode", "emacs")?
             .set_default("keymap_mode_shell", "auto")?
             .set_default("keymap_cursor", HashMap::<String, String>::new())?

crates/atuin/src/command/client/search/interactive.rs

@@ -204,7 +204,7 @@ impl State {
         let esc_allow_exit = !(self.tab_index == 0 && self.keymap_mode == KeymapMode::VimInsert);
 
         // support ctrl-a prefix, like screen or tmux
-        if ctrl && input.code == KeyCode::Char('a') {
+        if ctrl && input.code == KeyCode::Char(settings.keys.prefix.chars().next().unwrap_or('a')) {
             self.prefix = true;
             return InputAction::Continue;
         }