test(timetable): Phase C — 67 new tests (pure logic + composables + store + schemas)

apps/app/tests/unit/lib/timetable/:
  - snap.test.ts (5)            — rounding, clamp, edge cases
  - time-grid.test.ts (6)       — px↔min↔ISO roundtrips, formatTickLabel
  - conflict.test.ts (8)        — overlap, endpoint-touching, lane/stage scoping, cancelled exclusion
  - b2b.test.ts (6)             — 0min, 2:59, 3:01, overlap, side-set mapping, threshold constant
  - capacity.test.ts (7)        — null capacity, missing data, warn/critical, crew+guests preference
  - lane.test.ts (8)            — Pass 1 + Pass 2, cascade-bump preview, cancelled exclusion

apps/app/tests/unit/composables/:
  - useTimetableMutations.test.ts (5) — Idempotency-Key header, optimistic + cascade,
                                         409 VersionMismatch surfaced, park sends null,
                                         createStage POST path
  - useDragOrClick.test.ts (3)        — onClick fires under threshold, onDragStart+End
                                         above threshold, Esc cancels mid-flight

apps/app/tests/unit/schemas/timetable.test.ts (8) — payload + response zod parsers
apps/app/tests/unit/lib/idempotencyKey.test.ts (3) — 6-30 char range, 24-hex, uniqueness
apps/app/tests/unit/stores/useTimetableStore.test.ts (5) — defaults, toggleStatus, drag state, null guard

Refactor: useTimetableMutations.move now throws Error instances (no-throw-literal)
so AxiosError.message and the VersionMismatchError shape both bubble through .catch().

Test count: 252 → 319 (+67). All 42 files pass.

Out of scope this session (added to BACKLOG):
- ART-PERFORMANCEBLOCK-COMPONENT-TESTS — Vuetify intentionally not loaded in
  vitest.config.ts; a Vuexy-stub setup for component-mount tests is one PR of
  its own. Pure rendering logic (capacity, B2B, conflict) is fully covered at
  the lib/ layer.
- ART-AXE-CORE-A11Y-TESTS — axe-core not yet installed in the repo. The
  aria-label structure on PerformanceBlock + aria-live on the page entry are
  authored to pass an axe scan when added.
- ART-INTEGRATION-FLOW-TEST — full add → drag → resize → park flow needs
  Vuetify + router + msw setup; defer with the component tests above.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/app/tests/unit/lib/timetable/capacity.test.ts

@@ -0,0 +1,76 @@
+import { describe, expect, it } from 'vitest'
+import { CAPACITY_TOLERANCE, evaluateCapacity } from '@/lib/timetable/capacity'
+import type { ArtistEngagement, Performance, Stage } from '@/types/timetable'
+
+const stage: Stage = {
+  id: 's1',
+  event_id: 'ev1',
+  name: 'Hardstyle',
+  color: '#ff0000',
+  capacity: 1000,
+  sort_order: 0,
+  created_at: null,
+  updated_at: null,
+}
+
+const perf: Performance = {
+  id: 'p1',
+  engagement_id: 'e1',
+  event_id: 'ev1',
+  stage_id: 's1',
+  lane: 0,
+  lane_resolved: 0,
+  start_at: null,
+  end_at: null,
+  version: 0,
+  notes: null,
+  warnings: [],
+  created_at: null,
+  updated_at: null,
+  deleted_at: null,
+}
+
+function eng(crew: number, guests: number, draw: number | null = null): ArtistEngagement {
+  return {
+    crew_count: crew,
+    guests_count: guests,
+    artist: draw === null ? undefined : { default_draw: draw } as ArtistEngagement['artist'],
+  } as ArtistEngagement
+}
+
+describe('evaluateCapacity', () => {
+  it('returns null when stage has no capacity', () => {
+    expect(evaluateCapacity(perf, { ...stage, capacity: null }, eng(0, 0, 500))).toBeNull()
+  })
+
+  it('returns null when no expected attendance is available', () => {
+    expect(evaluateCapacity(perf, stage, eng(0, 0))).toBeNull()
+  })
+
+  it('returns null when below the tolerance', () => {
+    expect(evaluateCapacity(perf, stage, eng(0, 0, 1100))).toBeNull()
+  })
+
+  it('returns warn when ratio between tolerance and 1.5×', () => {
+    const result = evaluateCapacity(perf, stage, eng(0, 0, 1200))
+
+    expect(result?.level).toBe('warn')
+  })
+
+  it('returns critical when ratio > 1.5', () => {
+    const result = evaluateCapacity(perf, stage, eng(0, 0, 1700))
+
+    expect(result?.level).toBe('critical')
+  })
+
+  it('prefers crew + guests when present', () => {
+    const result = evaluateCapacity(perf, stage, eng(800, 800))
+
+    expect(result?.expected).toBe(1600)
+    expect(result?.level).toBe('critical')
+  })
+
+  it('exposes the tolerance constant', () => {
+    expect(CAPACITY_TOLERANCE).toBeGreaterThan(1)
+  })
+})