feat(markdown): KB/process render + working in-document anchor links

KB/process content was shown via a bare unsanitized ReactMarkdown in the
ops view dialog (the /ops/[id] route is the editor, not a view). Route
it through the shared SafeMarkdown instead. New dependency-free
lib/markdown-anchors.ts (heading-text flatten, GitHub-ish slug,
per-render dedupe, in-doc href test; unit-tested) is wired into both
SafeMarkdown and MarkdownBody so headings get stable ids and a
[link](#heading) resolves. In-document links no longer force a new tab,
which previously broke the anchor jump for policies/proposals too.
rehype-slug was not added (no offline install); the helper is equivalent
and tested.

__tests__/markdown-anchors.test.ts

@@ -0,0 +1,57 @@
+import { describe, it, expect } from 'vitest'
+import {
+  headingText,
+  slugifyHeading,
+  makeHeadingSlugger,
+  isInDocumentHref,
+} from '@/lib/markdown-anchors'
+
+describe('headingText', () => {
+  it('reads strings and numbers', () => {
+    expect(headingText('Hello')).toBe('Hello')
+    expect(headingText(42)).toBe('42')
+  })
+  it('flattens arrays and element children', () => {
+    expect(headingText(['Get ', 'started'])).toBe('Get started')
+    expect(headingText({ props: { children: ['Bold ', { props: { children: 'bit' } }] } })).toBe('Bold bit')
+  })
+  it('ignores null/boolean', () => {
+    expect(headingText(null)).toBe('')
+    expect(headingText(true)).toBe('')
+  })
+})
+
+describe('slugifyHeading', () => {
+  it('lowercases, strips punctuation, hyphenates', () => {
+    expect(slugifyHeading('Overview')).toBe('overview')
+    expect(slugifyHeading('  Getting Started!  ')).toBe('getting-started')
+    expect(slugifyHeading('A & B / C')).toBe('a-b-c')
+  })
+  it('collapses repeats and trims hyphens', () => {
+    expect(slugifyHeading('-- weird   spacing --')).toBe('weird-spacing')
+  })
+})
+
+describe('makeHeadingSlugger', () => {
+  it('dedupes repeated headings within a document', () => {
+    const slug = makeHeadingSlugger()
+    expect(slug('Setup')).toBe('setup')
+    expect(slug('Setup')).toBe('setup-1')
+    expect(slug('Setup')).toBe('setup-2')
+    expect(slug('Other')).toBe('other')
+  })
+  it('falls back to "section" for empty headings', () => {
+    const slug = makeHeadingSlugger()
+    expect(slug('')).toBe('section')
+    expect(slug('   ')).toBe('section-1')
+  })
+})
+
+describe('isInDocumentHref', () => {
+  it('is true only for hash links', () => {
+    expect(isInDocumentHref('#overview')).toBe(true)
+    expect(isInDocumentHref('https://example.com')).toBe(false)
+    expect(isInDocumentHref('/ops')).toBe(false)
+    expect(isInDocumentHref(undefined)).toBe(false)
+  })
+})