feat: internal links widget with counts and suggestions

- E10 golem15-seo-links in the SEO tab after the graph preview (types
  with a body): inbound and outbound counts from the last finished crawl,
  the orphan warning, up to 10 pages to link to (Copy address) and 10
  that could link here
- classes/linkgraph.go builds the report from the crawl's pages and
  links; the crawler's orphan suggestions share NormalText
- GET /_seo/api/v1/links and seo_get_link_suggestions; widget action
  seo_links mapped in AdminOperations
- element bundle rebuilt

tests/elements/links.test.ts

@@ -0,0 +1,134 @@
+import { afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
+import { labelsFor } from '../../assets/src/elements/labels'
+import type { LinksData } from '../../assets/src/elements/links'
+import { HostFailure, mountWidget, settle } from './host'
+
+// E10 golem15-seo-links (UI-SPEC C19, D-82).
+
+beforeAll(async () => {
+  await import('../../assets/src/elements/index')
+})
+
+afterEach(() => {
+  vi.unstubAllGlobals()
+  vi.useRealTimers()
+  document.body.replaceChildren()
+})
+
+const en = labelsFor('en')
+
+const crawled: LinksData = {
+  crawledAt: '2026-11-04T10:00:00Z',
+  inbound: 0,
+  outbound: 3,
+  orphan: true,
+  out: [{ phrase: 'shiitake', title: 'Shiitake', url: 'https://example.com/pages/shiitake' }],
+  in: [{ phrase: 'lwia grzywa', title: 'Oyster', adminUrl: '/backend/acme/pages/pages/update/3' }],
+}
+
+function stubClipboard(): { writes: string[] } {
+  const writes: string[] = []
+  vi.stubGlobal('navigator', {
+    ...navigator,
+    clipboard: {
+      writeText: (text: string) => {
+        writes.push(text)
+        return Promise.resolve()
+      },
+    },
+  })
+  return { writes }
+}
+
+describe('E10 golem15-seo-links', () => {
+  it('asks for the links of the shown locale on connect and renders counters, the orphan callout and both lists', async () => {
+    stubClipboard()
+    const host = mountWidget('golem15-seo-links', { attrs: { 'ui-locale': 'en' }, answer: () => crawled })
+    await settle()
+    expect(host.posted).toEqual([{ op: 'links', locale: '' }])
+    const node = host.node
+    const values = [...node.querySelectorAll('.summer-stat__value')].map((n) => n.textContent)
+    expect(values).toEqual(['0', '3'])
+    expect([...node.querySelectorAll('.summer-stat__label')].map((n) => n.textContent)).toEqual([en.linksInbound, en.linksOutbound])
+    expect(node.textContent).toContain('From the crawl of ')
+    expect(node.querySelector('.summer-callout--warning')!.textContent).toContain(en.linksOrphanTitle)
+    const headings = [...node.querySelectorAll('.seo-links__heading')].map((n) => n.textContent)
+    expect(headings).toEqual([en.linksOut, en.linksIn])
+    const out = node.querySelector('.seo-links__list--out .seo-links__row')!
+    expect(out.textContent).toContain('“shiitake” → Shiitake')
+    const link = out.querySelector('a')!
+    expect(link.getAttribute('href')).toBe('https://example.com/pages/shiitake')
+    expect(link.target).toBe('_blank')
+    expect(link.rel).toBe('noopener')
+    const inbound = node.querySelector('.seo-links__list--in .seo-links__row a')!
+    expect(inbound.getAttribute('href')).toBe('/backend/acme/pages/pages/update/3')
+    expect(node.querySelector('.seo-links__none')).toBeNull()
+    expect(node.getAttribute('aria-busy')).toBe('false')
+  })
+
+  it('shows notCrawled instead of counters before a crawl and none under empty lists', async () => {
+    const host = mountWidget('golem15-seo-links', {
+      attrs: { 'ui-locale': 'en' },
+      answer: () => ({ crawledAt: null, inbound: null, outbound: null, orphan: false, out: [], in: [] }),
+    })
+    await settle()
+    const node = host.node
+    expect(node.querySelector('.summer-stats')).toBeNull()
+    expect(node.textContent).toContain(en.linksNotCrawled)
+    expect(node.querySelector('.summer-callout')).toBeNull()
+    expect(node.querySelectorAll('.seo-links__none')).toHaveLength(2)
+    expect(node.querySelector('.seo-links__none')!.textContent).toBe(en.linksNone)
+  })
+
+  it('shows the checking line with aria-busy while loading and the danger line on failure', async () => {
+    const host = mountWidget('golem15-seo-links', {
+      attrs: { 'ui-locale': 'pl' },
+      answer: () => {
+        throw new HostFailure('down')
+      },
+    })
+    await Promise.resolve()
+    expect(host.node.getAttribute('aria-busy')).toBe('true')
+    expect(host.node.querySelector('.seo-links__checking')!.getAttribute('role')).toBe('status')
+    await settle()
+    const error = host.node.querySelector('.seo-links__error')!
+    expect(error.textContent).toBe(labelsFor('pl').linksFailed)
+    expect(error.getAttribute('role')).toBe('status')
+    expect(host.node.getAttribute('aria-busy')).toBe('false')
+  })
+
+  it('copies the address and says so for two seconds', async () => {
+    const clip = stubClipboard()
+    const host = mountWidget('golem15-seo-links', { attrs: { 'ui-locale': 'en' }, answer: () => crawled })
+    await settle()
+    vi.useFakeTimers()
+    const button = host.node.querySelector<HTMLButtonElement>('.seo-links__copy')!
+    expect(button.textContent).toBe(en.linksCopy)
+    button.click()
+    await Promise.resolve()
+    await Promise.resolve()
+    expect(clip.writes).toEqual(['https://example.com/pages/shiitake'])
+    expect(host.node.querySelector('.seo-links__status')!.textContent).toBe(en.linksCopied)
+    vi.advanceTimersByTime(2000)
+    expect(host.node.querySelector('.seo-links__status')!.textContent).toBe('')
+  })
+
+  it('hides Copy address without a clipboard and keeps the address as text', async () => {
+    vi.stubGlobal('navigator', { ...navigator, clipboard: undefined })
+    const host = mountWidget('golem15-seo-links', { attrs: { 'ui-locale': 'en' }, answer: () => crawled })
+    await settle()
+    expect(host.node.querySelector('.seo-links__copy')).toBeNull()
+    expect(host.node.querySelector('.seo-links__url')!.textContent).toBe('https://example.com/pages/shiitake')
+  })
+
+  it('asks again on the ML locale switch', async () => {
+    const host = mountWidget('golem15-seo-links', { attrs: { 'ui-locale': 'en' }, answer: () => crawled })
+    await settle()
+    window.dispatchEvent(new CustomEvent('summer:ml-locale', { detail: 'pl' }))
+    await settle()
+    expect(host.posted).toEqual([
+      { op: 'links', locale: '' },
+      { op: 'links', locale: 'pl' },
+    ])
+  })
+})