chore(repo): restructure as monorepo with server and client workspaces

- move NestJS app into server/ subdirectory
- add client/ React+TypeScript (Vite) app with Hello World
- update docker-compose to build and run both services
- add root package.json declaring npm workspaces
- update .gitignore to cover node_modules and dist at all depths

server/jest.config.js

@@ -0,0 +1,15 @@
+/** @type {import('jest').Config} */
+module.exports = {
+  moduleFileExtensions: ['js', 'json', 'ts'],
+  rootDir: '.',
+  testRegex: 'test/.*\\.spec\\.ts$',
+  transform: {
+    '^.+\\.ts$': ['ts-jest', { tsconfig: 'test/tsconfig.json' }],
+  },
+  moduleNameMapper: {
+    '^jsdom$': '<rootDir>/test/__mocks__/jsdom.ts',
+    '^playwright$': '<rootDir>/test/__mocks__/playwright.ts',
+    '^@mozilla/readability$': '<rootDir>/test/__mocks__/readability.ts',
+  },
+  testEnvironment: 'node',
+};