undo: header buttons, shortcuts, wiring

- App provides HistoryHandle as context (both build modes; stacks stay
  empty on the server) and passes it to persist::init_hydrated
- persist: init_hydrated starts undo tracking after the localStorage
  load (first captured state = saved state, not mock); clear_all and
  apply_import call undo::before_replace so they are undoable
- header: Отменить/Вернуть buttons with disabled states driven by the
  reactive stack depths; Ctrl+Z / Ctrl+Shift+Z / Ctrl+Y via a window
  keydown listener that skips editable targets (browser owns those)
- SCSS: disabled control buttons dim out

src/app.rs

@@ -32,11 +32,12 @@ pub fn App() -> impl IntoView {
     let store = Store::new(Dashboard::mock());
     provide_context(store.clone());
     provide_context(ModalState::new());
+    provide_context(crate::state::undo::HistoryHandle::new(store.clone()));
     console_error_panic_hook::set_once();
 
-    // Client-only: load the saved state after mount, then autosave.
+    // Client-only: load the saved state after mount, then autosave + undo.
     #[cfg(feature = "hydrate")]
-    crate::state::persist::init_hydrated(&store);
+    crate::state::persist::init_hydrated(&store, &expect_context::<crate::state::undo::HistoryHandle>());
 
     let modal = expect_context::<ModalState>();
 

src/components/header.rs

@@ -6,18 +6,24 @@ use wasm_bindgen::JsCast;
 use crate::components::modal::ModalState;
 use crate::prelude::*;
 use crate::state::persist::{ apply_import, clear_all, export_download };
+use crate::state::undo::HistoryHandle;
 
 /// Campaign header: editable name, campaign image, in-game date and
-/// session steppers, and the persistence controls.
+/// session steppers, the persistence controls, and undo/redo.
 ///
 /// Save downloads the dashboard as `dashboard.json`, Load imports one via
 /// a hidden file picker (with a confirm), Clear wipes to the blank
 /// campaign (with a confirm). Changes also autosave to localStorage
-/// (see `crate::state::persist`).
+/// (see `crate::state::persist`) and feed the undo history (see
+/// `crate::state::undo`); the undo/redo buttons and the Ctrl+Z /
+/// Ctrl+Shift+Z / Ctrl+Y shortcuts revert the last edit bursts.
 #[component]
 pub fn Header () -> impl IntoView {
     let state = expect_context::<Context>();
     let modal = expect_context::<ModalState>();
+    let history = expect_context::<HistoryHandle>();
+    let undo_depth = history.undo_depth();
+    let redo_depth = history.redo_depth();
     let file_input = NodeRef::<leptos::html::Input>::new();
     let campaign = state.campaign();
     let date = state.date();
@@ -123,6 +129,16 @@ pub fn Header () -> impl IntoView {
                     <button on:click=on_save>"Сохранить"</button>
                     <button on:click=on_load>"Загрузить"</button>
                     <button on:click=on_clear>"Очистить"</button>
+                    <button
+                        on:click=move |_| history.undo()
+                        disabled=move || undo_depth.get() == 0
+                        title="Отменить (Ctrl+Z)"
+                    >"Отменить"</button>
+                    <button
+                        on:click=move |_| history.redo()
+                        disabled=move || redo_depth.get() == 0
+                        title="Вернуть (Ctrl+Shift+Z или Ctrl+Y)"
+                    >"Вернуть"</button>
                 </div>
             </section>
             <input type="file" accept=".json,application/json" style="display: none" node_ref=file_input on:change=on_file/>

style/_header.scss

@@ -59,6 +59,11 @@ header {
             line-height: 1em;
             margin: 2px 5px;
             @include mixins.button;
+
+            &:disabled {
+                opacity: 0.45;
+                cursor: default;
+            }
         }
     }