feat: implement interactive lesson management and update command handling

src/app/mode/mod.rs

@@ -1,8 +1,6 @@
 //! TUI mode definitions and per-mode input/action handlers, one submodule
 //! per overlay/mode (bash, editor, effort, mcp, quit confirm, rewind, etc.).
 
-use serde::{Deserialize, Serialize};
-
 pub mod bash;
 pub mod editor;
 pub mod effort;
@@ -14,23 +12,4 @@ pub mod quit_confirm;
 pub mod rewind;
 pub mod settings;
 pub mod todo;
-
-/// Which input/overlay mode the TUI is currently in; drives both key
-/// routing (`controller/input.rs`) and rendering.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-pub enum ModeKind {
-    Chat,
-    Bash,
-    Workflow,
-    Help,
-    Settings,
-    QuitConfirm,
-
-    KeyInput,
-    Editor,
-    Effort,
-    Mcp,
-    Todo,
-    Rewind,
-    Loading,
-}
+pub mod learning;