test: run the suite and benchmark with Bun's native test runner

Replace Vitest with bun test across the whole suite. A preload compiles
components through Angular's JIT transform with inlined templates, sets
up jsdom, TestBed and zoneless change detection, and a small shim covers
the Vitest APIs bun:test lacks. Files run isolated, real-worker specs
spawn the running Bun, and line coverage from lcov is converted to the
existing HTML and Cobertura reports. The CI benchmark replaces its heap
cap with a container memory limit. Vitest, Jest, Nx and their Vite
configuration are removed.

Refs #291

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/services/translation-service.ts

@@ -1,4 +1,3 @@
-/// <reference types="vite/client" />
 import { Injectable, inject, Injector, computed } from '@angular/core';
 import { storedSignal } from '../shared/utils/stored-signal';
 import type { PlanOutcome, RemainingBalance } from './leave-planner.service';