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.

components/safe-markdown.tsx

@@ -1,9 +1,11 @@
 'use client'
 
+import type { ReactNode } from 'react'
 import ReactMarkdown from 'react-markdown'
 import remarkGfm from 'remark-gfm'
 import rehypeRaw from 'rehype-raw'
 import rehypeSanitize, { defaultSchema } from 'rehype-sanitize'
+import { makeHeadingSlugger, isInDocumentHref } from '@/lib/markdown-anchors'
 
 // Renders admin-authored markdown that MAY contain a constrained subset of raw
 // HTML. rehype-raw parses the HTML; rehype-sanitize then strips anything
@@ -27,11 +29,35 @@ const schema = {
 }
 
 export function SafeMarkdown({ children, className }: { children: string; className?: string }) {
+  // Per-render so heading ids are stable and de-duplicated within this doc.
+  const slug = makeHeadingSlugger()
+  const heading = (Tag: 'h1' | 'h2' | 'h3' | 'h4' | 'h5' | 'h6') =>
+    function H({ children: c }: { children?: ReactNode }) {
+      return <Tag id={slug(c)}>{c}</Tag>
+    }
   return (
     <div className={`prose prose-sm prose-neutral dark:prose-invert max-w-none break-words ${className ?? ''}`}>
       <ReactMarkdown
         remarkPlugins={[remarkGfm]}
         rehypePlugins={[rehypeRaw, [rehypeSanitize, schema]]}
+        components={{
+          h1: heading('h1'),
+          h2: heading('h2'),
+          h3: heading('h3'),
+          h4: heading('h4'),
+          h5: heading('h5'),
+          h6: heading('h6'),
+          // In-document links (#section) must stay in the page so the anchor
+          // jump works; everything else opens safely in a new tab.
+          a: ({ href, children: c }) =>
+            isInDocumentHref(href) ? (
+              <a href={href}>{c}</a>
+            ) : (
+              <a href={href} target="_blank" rel="noopener noreferrer">
+                {c}
+              </a>
+            ),
+        }}
       >
         {children}
       </ReactMarkdown>