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/planning-objectives.spec.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest';
+import { describe, expect, it } from 'bun:test';
 import {
 	compareObjectiveLists,
 	compareObjectiveValues,
@@ -174,7 +174,7 @@ describe('composable planning objectives', () => {
 
 	it.each([
 		null,
-		[],
+		[[]],
 		{ ...OPTIMIZATION_PRESETS.shortSequenceDeficit, conditions: ['internal', 'internal'] },
 		{ ...OPTIMIZATION_PRESETS.longestWorkSequence, direction: 'up' },
 		{ ...OPTIMIZATION_PRESETS.unplacedAtRisk, conditions: new Array(1) },