feat(overlay): forward mpv mouse and wheel bindings through overlay

- Accept WHEEL_UP/DOWN/LEFT/RIGHT (with modifiers) in keybindings, the plugin, and the settings key editor
- Forward mpv's MBTN_* and WHEEL_* bindings from the overlay so double-click fullscreen, wheel volume, and similar inputs work on Hyprland; SubMiner bindings and right-click pause still win
- Notify the overlay via mpv-input-bindings:changed when mpv's key set changes, fixing dead imported keys when the overlay loads before mpv connects
- Sync README requirements/quick start with the installation guide and fix the Arch MeCab install command (AUR mecab-git)

src/core/services/session-bindings.test.ts

@@ -212,12 +212,13 @@ test('compileSessionBindings resolves CommandOrControl in DOM key strings per pl
   );
 });
 
-test('compileSessionBindings supports mpv mouse button keybindings', () => {
+test('compileSessionBindings supports mpv mouse button and wheel keybindings', () => {
   const result = compileSessionBindings({
     shortcuts: createShortcuts(),
     keybindings: [
       createKeybinding('MBTN_BACK', ['sub-seek', -1]),
       createKeybinding('Shift+MBTN_FORWARD', ['sub-seek', 1]),
+      createKeybinding('Ctrl+WHEEL_UP', ['add', 'sub-scale', 0.1]),
     ],
     platform: 'win32',
   });
@@ -232,6 +233,7 @@ test('compileSessionBindings supports mpv mouse button keybindings', () => {
     [
       { code: 'MBTN_BACK', modifiers: [], command: ['sub-seek', -1] },
       { code: 'MBTN_FORWARD', modifiers: ['shift'], command: ['sub-seek', 1] },
+      { code: 'WHEEL_UP', modifiers: ['ctrl'], command: ['add', 'sub-scale', 0.1] },
     ],
   );
 });

src/core/services/session-bindings.ts

@@ -34,12 +34,16 @@ type DraftBinding = {
 };
 
 const MODIFIER_ORDER: SessionKeyModifier[] = ['ctrl', 'alt', 'shift', 'meta'];
-const MPV_MOUSE_BUTTON_CODES = new Set([
+const MPV_MOUSE_CODES = new Set([
   'MBTN_LEFT',
   'MBTN_MID',
   'MBTN_RIGHT',
   'MBTN_BACK',
   'MBTN_FORWARD',
+  'WHEEL_UP',
+  'WHEEL_DOWN',
+  'WHEEL_LEFT',
+  'WHEEL_RIGHT',
 ]);
 
 const SESSION_SHORTCUT_ACTIONS: Array<{
@@ -82,7 +86,7 @@ function isValidCommandEntry(value: unknown): value is string | number {
 
 function normalizeCodeToken(
   token: string,
-  options: { allowMouseButtons?: boolean } = {},
+  options: { allowMouseInput?: boolean } = {},
 ): string | null {
   const normalized = token.trim();
   if (!normalized) return null;
@@ -93,9 +97,9 @@ function normalizeCodeToken(
       .map((letter) => `Key${letter.toUpperCase()}`)
       .join('-');
   }
-  if (options.allowMouseButtons === true) {
+  if (options.allowMouseInput === true) {
     const normalizedMouse = normalized.toUpperCase();
-    if (MPV_MOUSE_BUTTON_CODES.has(normalizedMouse)) {
+    if (MPV_MOUSE_CODES.has(normalizedMouse)) {
       return normalizedMouse;
     }
   }
@@ -270,7 +274,7 @@ export function parseSessionBindingKey(
     };
   }
 
-  const code = normalizeCodeToken(keyToken, { allowMouseButtons: true });
+  const code = normalizeCodeToken(keyToken, { allowMouseInput: true });
   if (!code) {
     return {
       key: null,