Completes Phase 2a: geschichten/[id], persons/[id]/edit and admin/tags/[id]
page specs now provide a real createConfirmService() via render context
instead of mocking confirm.svelte. Zero confirm.svelte vi.mocks remain
across the client suite (AC#4). Part of #560.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>