build: migrate build system to Vite and test runner to Vitest & Remove

depracated husky usage

- Replace Webpack with Vite for faster client bundling and HMR.
- Migrate tests from Jest to Vitest and update configuration.
- Update Web Worker instantiation to standard ESM syntax.
- Implement Env utility in `src/core` for safe, hybrid environment
  variable access (Vite vs Node).
- Refactor configuration loaders to remove direct `process.env`
  dependencies in shared code.
- Update TypeScript environment definitions and project scripts for the
  new toolchain.
- Remove the [depracated usage of the
  husky](https://github.com/typicode/husky/releases/tag/v9.0.1).

build(vite): implement robust git commit resolution with fallback

tests/client/components/FluentSlider.test.ts

@@ -1,11 +1,8 @@
-/**
- * @jest-environment jsdom
- */
 import { FluentSlider } from "../../../src/client/components/FluentSlider";
 
 // Mock the translateText function
-jest.mock("../../../src/client/Utils", () => ({
-  translateText: jest.fn((key: string) => key),
+vi.mock("../../../src/client/Utils", () => ({
+  translateText: vi.fn((key: string) => key),
 }));
 
 describe("FluentSlider", () => {
@@ -84,7 +81,7 @@ describe("FluentSlider", () => {
 
   describe("Value-Changed Event - CRITICAL FOR BUG FIX", () => {
     it("should dispatch CustomEvent with detail.value (not event.target.value)", async () => {
-      const eventSpy = jest.fn();
+      const eventSpy = vi.fn();
       slider.addEventListener("value-changed", eventSpy);
 
       const rangeInput = slider.shadowRoot?.querySelector(
@@ -107,7 +104,7 @@ describe("FluentSlider", () => {
     });
 
     it("should not dispatch event on input, only on change", async () => {
-      const eventSpy = jest.fn();
+      const eventSpy = vi.fn();
       slider.addEventListener("value-changed", eventSpy);
 
       const rangeInput = slider.shadowRoot?.querySelector(
@@ -128,7 +125,7 @@ describe("FluentSlider", () => {
 
     it("should work with the handler pattern used in HostLobbyModal", async () => {
       // This simulates the actual handler code in HostLobbyModal.ts:656-660
-      const mockHandler = jest.fn((e: Event) => {
+      const mockHandler = vi.fn((e: Event) => {
         const customEvent = e as CustomEvent<{ value: number }>;
         const value = customEvent.detail.value;
         if (isNaN(value) || value < 0 || value > 400) {
@@ -154,7 +151,7 @@ describe("FluentSlider", () => {
 
     it("should work with the handler pattern used in SinglePlayerModal", async () => {
       // This simulates the actual handler code in SinglePlayerModal.ts:444-451
-      const mockHandler = jest.fn((e: Event) => {
+      const mockHandler = vi.fn((e: Event) => {
         const customEvent = e as CustomEvent<{ value: number }>;
         const value = customEvent.detail.value;
         if (isNaN(value) || value < 0 || value > 400) {