fix: tighten type safety in boot services

- Add AppLifecycleShape and OverlayModalInputStateShape constraints
  so TAppLifecycleApp and TOverlayModalInputState generics are bounded
- Remove unsafe `as { handleModalInputStateChange? }` cast — now
  directly callable via the constraint
- Use `satisfies AppLifecycleShape` for structural validation on the
  appLifecycleApp object literal
- Document Electron App.on incompatibility with simple signatures

src/main/boot/services.test.ts

@@ -24,7 +24,7 @@ test('createMainBootServices builds boot-phase service bundle', () => {
     { scope: string; warn: () => void; info: () => void; error: () => void },
     { registry: boolean },
     { getModalWindow: () => null },
-    { inputState: boolean },
+    { inputState: boolean; getModalInputExclusive: () => boolean; handleModalInputStateChange: (isActive: boolean) => void },
     { measurementStore: boolean },
     { modalRuntime: boolean },
     { mpvSocketPath: string; texthookerPort: number },
@@ -50,7 +50,7 @@ test('createMainBootServices builds boot-phase service bundle', () => {
         setPathValue = value;
       },
       quit: () => {},
-      on: (event) => {
+      on: (event: string) => {
         appOnCalls.push(event);
         return {};
       },
@@ -80,7 +80,7 @@ test('createMainBootServices builds boot-phase service bundle', () => {
     createOverlayManager: () => ({
       getModalWindow: () => null,
     }),
-    createOverlayModalInputState: () => ({ inputState: true }),
+    createOverlayModalInputState: () => ({ inputState: true, getModalInputExclusive: () => false, handleModalInputStateChange: () => {} }),
     createOverlayContentMeasurementStore: () => ({ measurementStore: true }),
     getSyncOverlayShortcutsForModal: () => () => {},
     getSyncOverlayVisibilityForModal: () => () => {},

src/main/boot/services.ts

@@ -1,6 +1,18 @@
-import { BrowserWindow } from 'electron';
+import type { BrowserWindow } from 'electron';
 import { ConfigStartupParseError } from '../../config';
 
+export interface AppLifecycleShape {
+  requestSingleInstanceLock: () => boolean;
+  quit: () => void;
+  on: (event: string, listener: (...args: unknown[]) => void) => unknown;
+  whenReady: () => Promise<void>;
+}
+
+export interface OverlayModalInputStateShape {
+  getModalInputExclusive: () => boolean;
+  handleModalInputStateChange: (isActive: boolean) => void;
+}
+
 export interface MainBootServicesParams<
   TConfigService,
   TAnilistTokenStore,
@@ -38,7 +50,8 @@ export interface MainBootServicesParams<
   app: {
     setPath: (name: string, value: string) => void;
     quit: () => void;
-    on: (event: any, listener: (...args: unknown[]) => void) => any;
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-function-type -- Electron App.on has 50+ overloaded signatures
+    on: Function;
     whenReady: () => Promise<void>;
   };
   shouldBypassSingleInstanceLock: () => boolean;
@@ -124,11 +137,11 @@ export function createMainBootServices<
   TLogger,
   TRuntimeRegistry,
   TOverlayManager extends { getModalWindow: () => BrowserWindow | null },
-  TOverlayModalInputState,
+  TOverlayModalInputState extends OverlayModalInputStateShape,
   TOverlayContentMeasurementStore,
   TOverlayModalRuntime,
   TAppState,
-  TAppLifecycleApp,
+  TAppLifecycleApp extends AppLifecycleShape,
 >(
   params: MainBootServicesParams<
     TConfigService,
@@ -212,8 +225,7 @@ export function createMainBootServices<
     overlayManager,
     overlayModalInputState,
     onModalStateChange: (isActive: boolean) =>
-      (overlayModalInputState as { handleModalInputStateChange?: (isActive: boolean) => void })
-        .handleModalInputStateChange?.(isActive),
+      overlayModalInputState.handleModalInputStateChange(isActive),
   });
   const appState = params.createAppState({
     mpvSocketPath: params.getDefaultSocketPath(),
@@ -242,7 +254,7 @@ export function createMainBootServices<
       return appLifecycleApp;
     },
     whenReady: () => params.app.whenReady(),
-  } as TAppLifecycleApp;
+  } satisfies AppLifecycleShape as TAppLifecycleApp;
 
   return {
     configDir,