feat(overlay): discover unclaimed mpv key bindings (#246)

src/types/runtime.ts

@@ -1,3 +1,4 @@
+import type { MpvInputBindingsSnapshot } from './session-bindings';
 import type {
   KikuFieldGroupingChoice,
   KikuFieldGroupingRequestData,
@@ -462,6 +463,7 @@ export interface ElectronAPI {
   setMecabEnabled: (enabled: boolean) => void;
   sendMpvCommand: (command: (string | number)[]) => void;
   getKeybindings: () => Promise<Keybinding[]>;
+  getMpvInputBindings: () => Promise<MpvInputBindingsSnapshot>;
   getSessionBindings: () => Promise<CompiledSessionBinding[]>;
   getConfiguredShortcuts: () => Promise<Required<ShortcutsConfig>>;
   dispatchSessionAction: (

src/types/session-bindings.ts

@@ -34,6 +34,11 @@ export interface SessionKeySpec {
   modifiers: SessionKeyModifier[];
 }
 
+export interface MpvInputBindingsSnapshot {
+  keys: string[];
+  blockedKeys: SessionKeySpec[];
+}
+
 export interface SessionBindingWarning {
   kind: 'unsupported' | 'conflict' | 'deprecated-config';
   path: string;