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/main/runtime/session-bindings-runtime.test.ts

@@ -71,6 +71,45 @@ test('persistSessionBindings keeps saved bindings when mpv reload notification f
   }
 });
 
+test('mpv input binding discovery notifies the overlay when the native key set changes', async () => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-session-native-keys-'));
+  let nativeKeys: unknown = [{ key: '9', cmd: 'add volume -5', priority: 25 }];
+  let notifications = 0;
+  const client = {
+    connected: false,
+    send: () => {},
+    requestProperty: async () => nativeKeys,
+  };
+  const runtime = createSessionBindingsRuntime({
+    configDir: root,
+    getKeybindings: () => [],
+    getConfiguredShortcuts: () => ({ multiCopyTimeoutMs: 1500 }) as never,
+    getResolvedConfig: () => ({ stats: { toggleKey: 's', markWatchedKey: 'w' } }) as ResolvedConfig,
+    getMpvClient: () => client,
+    setSessionBindings: () => {},
+    setSessionBindingsInitialized: () => {},
+    logWarn: () => {},
+    onMpvInputBindingsChanged: () => {
+      notifications += 1;
+    },
+  });
+  try {
+    runtime.persistSessionBindings([]);
+    await runtime.refreshMpvSessionBindings();
+    assert.equal(notifications, 0, 'nothing to announce before mpv connects');
+    client.connected = true;
+    await runtime.refreshMpvSessionBindings();
+    assert.equal(notifications, 1, 'first discovery after connecting must reach the overlay');
+    await runtime.refreshMpvSessionBindings();
+    assert.equal(notifications, 1, 'unchanged discovery must not create a refresh loop');
+    nativeKeys = [{ key: '0', cmd: 'ignore', priority: 25 }];
+    await runtime.refreshMpvSessionBindings();
+    assert.equal(notifications, 2, 'ignored keys still change what the overlay may forward');
+  } finally {
+    fs.rmSync(root, { recursive: true, force: true });
+  }
+});
+
 test('native prefix conflicts publish the same effective bindings to the overlay and plugin and recover', async () => {
   const root = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-session-conflict-'));
   const sequence: CompiledSessionBinding = {

src/main/runtime/session-bindings-runtime.ts

@@ -25,6 +25,10 @@ export interface SessionBindingsRuntimeDeps {
   setSessionBindingsInitialized: (initialized: boolean) => void;
   logWarn: (message: string, details?: unknown) => void;
   onBindingsChanged?: (bindings: CompiledSessionBinding[]) => void;
+  // Fires when mpv's own key bindings change, including the first discovery after
+  // connecting. The overlay's imported mpv keys depend on them even when the
+  // compiled session bindings stay identical.
+  onMpvInputBindingsChanged?: () => void;
   onWarning?: (warning: SessionBindingWarning) => void;
 }
 
@@ -41,6 +45,7 @@ export function createSessionBindingsRuntime(deps: SessionBindingsRuntimeDeps):
   let nativeSnapshot: {
     client: ReturnType<SessionBindingsRuntimeDeps['getMpvClient']>;
     keys: string[];
+    signature: string;
   } | null = null;
   let pending: {
     client: ReturnType<SessionBindingsRuntimeDeps['getMpvClient']>;
@@ -135,8 +140,15 @@ export function createSessionBindingsRuntime(deps: SessionBindingsRuntimeDeps):
       try {
         const raw = await client.requestProperty('input-bindings');
         if (client !== deps.getMpvClient() || !client.connected) return;
-        nativeSnapshot = { client, keys: parseMpvInputBindingKeys(raw, { includeIgnored: false }) };
+        const signature = JSON.stringify(parseMpvInputBindingKeys(raw));
+        const changed = nativeSnapshot?.client !== client || nativeSnapshot.signature !== signature;
+        nativeSnapshot = {
+          client,
+          keys: parseMpvInputBindingKeys(raw, { includeIgnored: false }),
+          signature,
+        };
         publishBindings();
+        if (changed) deps.onMpvInputBindingsChanged?.();
       } catch {
         // Keep the last successful snapshot if discovery is temporarily unavailable.
       }