Migrate JavaScript to TypeScript with full type safety

- Rename all .js/.jsx files to .ts/.tsx across resources/js and theme dirs
- Add TypeScript 6.0 with strict mode, tsconfig.json
- Add type definitions for Inertia page props, Alpine.js, Turbolinks
- Update vite.config.js entries to .ts/.tsx extensions
- Update all Blade @vite() calls to match new .ts/.tsx entry points
- Add TypeScript ESLint config (replacing unused Vue plugin)
- Add @types/react, @types/react-dom, @types/lodash
- Add typecheck script and integrate into check pipeline
- Full tsc --noEmit, ESLint, and production build pass cleanly

resources/js/types.d.ts

@@ -0,0 +1,31 @@
+declare module "alpinejs" {
+  interface Alpine {
+    data(name: string, callback: (...args: unknown[]) => Record<string, unknown>): void;
+    plugin(plugin: unknown): void;
+    start(): void;
+  }
+  const Alpine: Alpine;
+  export default Alpine;
+}
+
+declare module "@alpinejs/focus" {
+  const focus: unknown;
+  export default focus;
+}
+
+declare module "turbolinks" {
+  interface TurbolinksStatic {
+    start(): void;
+  }
+  const Turbolinks: TurbolinksStatic;
+  export default Turbolinks;
+}
+
+interface Window {
+  _: import("lodash").default;
+  axios: import("axios").AxiosStatic;
+  App: {
+    defaultReactions: string[];
+    isAuthenticated: boolean;
+  };
+}