fix(mixin): access platformService as property, not function, in PlatformServiceMixin

- Fix all computed properties to use platformService as a property
- Add descriptive @ts-expect-error comments for dynamic property access
- Resolves 'this.platformService is not a function' runtime error
- Lint clean

src/utils/PlatformServiceMixin.ts

@@ -121,30 +121,26 @@ export const PlatformServiceMixin = {
      * Platform detection utilities
      */
     isCapacitor(): boolean {
-      return (this as unknown as VueComponentWithMixin)
-        .platformService()
-        .isCapacitor();
+      // @ts-expect-error Accessing computed property value from Vue instance
+      return this["platformService"].isCapacitor();
     },
 
     isWeb(): boolean {
-      return (this as unknown as VueComponentWithMixin)
-        .platformService()
-        .isWeb();
+      // @ts-expect-error Accessing computed property value from Vue instance
+      return this["platformService"].isWeb();
     },
 
     isElectron(): boolean {
-      return (this as unknown as VueComponentWithMixin)
-        .platformService()
-        .isElectron();
+      // @ts-expect-error Accessing computed property value from Vue instance
+      return this["platformService"].isElectron();
     },
 
     /**
      * Platform capabilities
      */
     capabilities() {
-      return (this as unknown as VueComponentWithMixin)
-        .platformService()
-        .getCapabilities();
+      // @ts-expect-error Accessing computed property value from Vue instance
+      return this["platformService"].getCapabilities();
     },
   },