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/benchmark/leave-planner-benchmark.spec.ts

@@ -1,4 +1,4 @@
-import { vi } from 'vitest';
+import { vi } from '../../testing/vitest-compat';
 import { calculatePlanningAsyncInternal } from '../services/frozen-engine/leave-planner.core.frozen.mjs';
 import { createPlanningCalculation } from '../services/leave-planner.service';
 import {
@@ -78,7 +78,7 @@ describe('leave planner benchmark protocol', () => {
 				await calculatePlanningAsyncInternal({ ...request, calculationDate: '2024-01-01' });
 				calibrationMs = Math.min(calibrationMs, performance.now() - start);
 			}
-			// Direct writes skip Vitest's per-call "stdout |" headers and appear immediately.
+			// Direct stdout writes show each row as soon as its scenario finishes.
 			const print = (text: string) => process.stdout.write(`${text}\n`);
 			print(
 				`\nCalibration: frozen engine on "two years", best of 3 = ${calibrationMs.toFixed(1)} ms` +