feat(board): canonical board definition and BoardView (T2)

Encode the board as blocks of stacked-section columns (C1) and render it as
the ASCII-styled DOM grid (C2) with hover highlight and a select emit. Layout
mirrors the physical board (Client Satisfaction above Product Architecture;
Macroplan above Defect Visualisation, both left of Feature Kanban) and boxes
use true ISO 216 proportions (1:√2, each step up scaled by √2). Both views
render from the one definition; tests pin section presence, click, hover,
layout order, and a snapshot.

tests/board.spec.ts

@@ -0,0 +1,52 @@
+// @vitest-environment nuxt
+import { describe, it, expect } from 'vitest'
+import { mountSuspended } from '@nuxt/test-utils/runtime'
+import BoardView from '../app/components/BoardView.vue'
+import { board, sections } from '../app/board/definition'
+
+describe('BoardView', () => {
+  it('renders every block and section from the one definition', async () => {
+    const wrapper = await mountSuspended(BoardView)
+    for (const block of board) {
+      expect(wrapper.text()).toContain(block.title)
+    }
+    for (const section of sections) {
+      expect(wrapper.find(`[data-section-id="${section.id}"]`).exists()).toBe(true)
+      expect(wrapper.text()).toContain(section.label)
+    }
+  })
+
+  it('emits the stable section id on click', async () => {
+    const wrapper = await mountSuspended(BoardView)
+    await wrapper.find('[data-section-id="macroplan"]').trigger('click')
+    expect(wrapper.emitted('select')?.[0]).toEqual(['macroplan'])
+  })
+
+  it('highlights a section on hover', async () => {
+    const wrapper = await mountSuspended(BoardView)
+    const macroplan = wrapper.find('[data-section-id="macroplan"]')
+    expect(macroplan.classes()).not.toContain('is-hovered')
+    await macroplan.trigger('mouseenter')
+    expect(macroplan.classes()).toContain('is-hovered')
+    await macroplan.trigger('mouseleave')
+    expect(macroplan.classes()).not.toContain('is-hovered')
+  })
+
+  it('stacks and orders sections as on the physical board', async () => {
+    const wrapper = await mountSuspended(BoardView)
+    const order = wrapper
+      .findAll('[data-section-id]')
+      .map((el) => el.attributes('data-section-id'))
+    const at = (id: string) => order.indexOf(id)
+    // Product Architecture below Client Satisfaction (same column).
+    expect(at('client-satisfaction')).toBeLessThan(at('product-architecture'))
+    // Macroplan above Defect Visualisation, both left of Feature Kanban.
+    expect(at('macroplan')).toBeLessThan(at('defect-visualisation'))
+    expect(at('defect-visualisation')).toBeLessThan(at('feature-kanban'))
+  })
+
+  it('matches the rendered board snapshot', async () => {
+    const wrapper = await mountSuspended(BoardView)
+    expect(wrapper.html()).toMatchSnapshot()
+  })
+})