feat(planning): make optimization rules composable

Evaluate explicit, ordered optimization configurations through one shared
planner model. Add six editable presets, durable one-time legacy migration,
and consistent completed and cancelled plan provenance.

Include functional regressions and the agreed trace-removal and benchmark
follow-up specs. Performance acceptance remains in #78 under unchanged gates.

Refs: #70, #71, #72, #73, #74, #75, #76, #77, #78

src/app/app-settings.spec.ts

@@ -32,7 +32,7 @@ describe('Application Settings', () => {
 		localStorage.clear();
 		localStorage.setItem('app.language', JSON.stringify('en'));
 		localStorage.setItem('leaveBalances', savedBalances);
-		localStorage.setItem('vacationRules', '[]');
+		localStorage.setItem('vacationRules', '{"version":1,"rules":[]}');
 		localStorage.setItem('unrelated.entry', 'keep this value');
 		mediaQuery = Object.assign(new EventTarget(), {
 			matches: true,
@@ -461,7 +461,7 @@ describe('Application Settings', () => {
 			await (await dialog.getHarness(MatSlideToggleHarness)).check();
 			expect(localStorage.getItem('calendarSettings.showWeekNumbers')).toBe('true');
 			expect(localStorage.getItem('leaveBalances')).toBe(savedBalances);
-			expect(localStorage.getItem('vacationRules')).toBe('[]');
+			expect(localStorage.getItem('vacationRules')).toBe('{"version":1,"rules":[]}');
 			expect(localStorage.getItem('unrelated.entry')).toBe('keep this value');
 			expect(fixture.nativeElement.querySelectorAll('.week-number').length).toBeGreaterThan(
 				0,
@@ -490,7 +490,7 @@ describe('Application Settings', () => {
 			TestBed.resetTestingModule();
 			await createApp();
 			expect(localStorage.getItem('leaveBalances')).toBe(savedBalances);
-			expect(localStorage.getItem('vacationRules')).toBe('[]');
+			expect(localStorage.getItem('vacationRules')).toBe('{"version":1,"rules":[]}');
 			expect(localStorage.getItem('unrelated.entry')).toBe('keep this value');
 			expect(document.body.classList.contains('dark-mode')).toBe(true);
 			expect(