feat(dashboard): red-dot weak-point map on /defects (T7)

Overlay each filed defect as a red dot inside its section box with a
diagonal date label; cap visible dots and collapse the remainder to a
"+N more" using the authoritative per-section counts (T6).

Add an `overlay` scoped slot to BoardView (C2) so the dashboard can layer
dots without forking the board definition (F1); the reporting view leaves
it empty. DotMap groups the bounded feed by section and the /defects page
wires both endpoints.

tests/dotmap.nuxt.spec.ts

@@ -0,0 +1,59 @@
+// @vitest-environment nuxt
+import { describe, it, expect } from 'vitest'
+import { mountSuspended } from '@nuxt/test-utils/runtime'
+import type { VueWrapper } from '@vue/test-utils'
+import DotMap from '../app/components/DotMap.vue'
+
+// The section box the overlay dots are rendered inside (BoardView marks each
+// section with `data-section-id`).
+const section = (wrapper: VueWrapper, id: string) =>
+  wrapper.find(`[data-section-id="${id}"]`)
+
+describe('DotMap', () => {
+  it('renders a red dot with a date label inside the defect’s section', async () => {
+    const wrapper = await mountSuspended(DotMap, {
+      props: {
+        defects: [{ id: 'd1', sectionId: 'macroplan', createdAt: '2026-05-28T10:00:00Z' }],
+        counts: { macroplan: 1 },
+      },
+    })
+
+    const dots = section(wrapper, 'macroplan').findAll('[data-test="dot"]')
+    expect(dots).toHaveLength(1)
+    expect(dots[0]!.text()).toContain('28/05')
+
+    // A section with no defects shows no dots.
+    expect(section(wrapper, 'problem-solving').findAll('[data-test="dot"]')).toHaveLength(0)
+  })
+
+  it('caps visible dots and collapses the overflow to "+N more"', async () => {
+    const cap = 10
+    const defects = Array.from({ length: 15 }, (_, i) => ({
+      id: `d${i}`,
+      sectionId: 'feature-kanban',
+      createdAt: '2026-05-28T10:00:00Z',
+    }))
+
+    const wrapper = await mountSuspended(DotMap, {
+      // Feed holds 15 for this section but the true total is 42 (counts).
+      props: { defects, counts: { 'feature-kanban': 42 }, cap },
+    })
+
+    const box = section(wrapper, 'feature-kanban')
+    expect(box.findAll('[data-test="dot"]')).toHaveLength(cap)
+    const more = box.find('[data-test="more"]')
+    expect(more.exists()).toBe(true)
+    expect(more.text()).toContain('+32 more') // 42 total − 10 shown
+  })
+
+  it('shows no overflow marker when a section is at or below the cap', async () => {
+    const wrapper = await mountSuspended(DotMap, {
+      props: {
+        defects: [{ id: 'd1', sectionId: 'macroplan', createdAt: '2026-05-28T10:00:00Z' }],
+        counts: { macroplan: 1 },
+      },
+    })
+
+    expect(section(wrapper, 'macroplan').find('[data-test="more"]').exists()).toBe(false)
+  })
+})