feat: add lesson export and import functionality

- Implemented `LessonExport` and `LessonImport` actions in the action module.
- Added corresponding command parsing for lesson export and import.
- Created functions to handle lesson export and import in the memory module.
- Updated state management to reflect changes after lesson operations.
- Introduced deferred operations for handling asynchronous tasks in the event loop.
- Enhanced the tool execution context to include graduated checks for file operations.
- Added OAuth support with PKCE for secure authorization flows.
- Implemented a loopback server for handling OAuth redirects.
- Refactored various modules to improve code organization and maintainability.

src/app/runtime/actions/mod.rs

@@ -38,6 +38,12 @@ pub enum Action {
     QuitConfirm,
     Resize(u16, u16),
     Tick,
+    LessonExport {
+        path: String,
+    },
+    LessonImport {
+        path: String,
+    },
     RecordUsage {
         tokens_in: u64,
         tokens_out: u64,
@@ -224,6 +230,45 @@ pub fn apply_action(state: &mut AppStateRest, action: Action) {
             state.scroll.set_max_visible(w as usize);
             state.dirty = true;
         }
+        Action::LessonExport { path } => {
+            let dest = std::path::Path::new(&path);
+            if let Some(parent) = dest.parent() {
+                let _ = std::fs::create_dir_all(parent);
+            }
+            match crate::model::memory::export_lessons(&state.memory_dir, dest) {
+                Ok(_) => {
+                    state.push_toast(crate::app::state::types::Toast::new(
+                        crate::app::state::types::ToastKind::Success,
+                        format!("lessons exported to {}", path),
+                    ));
+                }
+                Err(e) => {
+                    state.push_toast(crate::app::state::types::Toast::new(
+                        crate::app::state::types::ToastKind::Error,
+                        format!("export failed: {}", e),
+                    ));
+                }
+            }
+            state.dirty = true;
+        }
+        Action::LessonImport { path } => {
+            let src = std::path::Path::new(&path);
+            match crate::model::memory::import_lessons(&state.memory_dir, src) {
+                Ok(count) => {
+                    state.push_toast(crate::app::state::types::Toast::new(
+                        crate::app::state::types::ToastKind::Success,
+                        format!("imported {} lessons from {}", count, path),
+                    ));
+                }
+                Err(e) => {
+                    state.push_toast(crate::app::state::types::Toast::new(
+                        crate::app::state::types::ToastKind::Error,
+                        format!("import failed: {}", e),
+                    ));
+                }
+            }
+            state.dirty = true;
+        }
         Action::Tick => {
             let now_ms = chrono::Utc::now().timestamp_millis();
             state.misc.drain_expired_toasts(now_ms);