fix: TOC double-entry + missing-section bugs after markdown-strip changes

Two bugs from the same root cause: hideSectionSlugs strips sections from
the rendered HTML body but DocumentToc reads its markdown items from the
precompiled siteData.documentIndex[path].toc list, which still contains
the stripped headings. Result on the user side:

1. 'Двойная кнопка Mitigation одна пустая' — TOC shows the original
   markdown 'Mitigations' heading (anchor target removed from body, so
   click goes nowhere) PLUS the JSX extraItem 'Mitigations (7)'. Two
   identical-looking entries, one broken.

2. 'Секция Mitigation исчезла' on Techniques where relatedMitigations.length
   was 0 — the JSX cards section was guarded with > 0 (correct) but the
   markdown-side strip ran unconditionally, hiding the markdown body's
   own '## Mitigations' prose. User saw neither cards nor prose.

Fixes:

  DocumentToc — accepts the same hideSectionSlugs prop. Markdown items
  filtered through the slug set before rendering; the TOC stays in
  sync with what's actually rendered in the body.

  TechniqueDetailPage / GroupDetailPage — hiddenSlugs is now computed
  conditionally:
    if (relatedMitigations.length > 0) hiddenSlugs.push('mitigations');
    if (relatedExamples.length > 0)    hiddenSlugs.push('real-world-examples');
    (Group: 'observed-techniques' / 'observed-examples' on equivalent
    counts.)
  Same hiddenSlugs passed both to InlineMarkdown (body strip) and to
  DocumentToc (TOC strip) so they can never disagree.

Group page also now exposes Observed Techniques + Worked Examples
extraItems to TOC (was missing — only Software used was wired).

Build clean. Should resolve both 'двойная кнопка' and 'секция исчезла'.

Author: iZonex

src/components/detail-pages/GroupDetailPage.tsx

@@ -53,6 +53,11 @@ export default function GroupDetailPage({
     .slice()
     .sort((a, b) => b.file.localeCompare(a.file));
 
+  // Strip markdown sections only when we render the JSX equivalent.
+  const hiddenSlugs: string[] = [];
+  if (observedTechniques.length > 0) hiddenSlugs.push("observed-techniques");
+  if (groupExamples.length > 0) hiddenSlugs.push("observed-examples");
+
   return (
     <section className="document-page technique-detail-page">
       <Breadcrumb onBack={onClose} items={breadcrumb} />
@@ -67,8 +72,11 @@ export default function GroupDetailPage({
           </div>
           <DocumentToc
             path={`actors/${actor.file}`}
+            hideSectionSlugs={hiddenSlugs}
             extraItems={[
-              { label: `Software used (${usesSoftware.length})`, slug: "section-software" },
+              ...(usesSoftware.length > 0 ? [{ label: `Software used (${usesSoftware.length})`, slug: "section-software" }] : []),
+              ...(observedTechniques.length > 0 ? [{ label: `Observed Techniques (${observedTechniques.length})`, slug: "section-techniques" }] : []),
+              ...(groupExamples.length > 0 ? [{ label: `Worked Examples (${groupExamples.length})`, slug: "section-worked-examples" }] : []),
             ]}
           />
           <div className="detail-actions">
@@ -95,7 +103,7 @@ export default function GroupDetailPage({
             <InlineMarkdown
               path={`actors/${actor.file}`}
               onOpenDoc={onOpenDoc}
-              hideSectionSlugs={["observed-techniques", "observed-examples"]}
+              hideSectionSlugs={hiddenSlugs}
             />
           </section>
 

src/components/detail-pages/TechniqueDetailPage.tsx

@@ -71,6 +71,12 @@ export default function TechniqueDetailPage({
     .map((sid) => allSpecs.find((s) => s.spec_id === sid))
     .filter((s): s is SpecRecord => Boolean(s));
 
+  // Strip a markdown section ONLY when we're going to render its JSX
+  // equivalent — otherwise the user sees neither prose nor cards.
+  const hiddenSlugs: string[] = [];
+  if (relatedMitigations.length > 0) hiddenSlugs.push("mitigations");
+  if (relatedExamples.length > 0) hiddenSlugs.push("real-world-examples");
+
   return (
     <section className="document-page technique-detail-page">
       <Breadcrumb onBack={onClose} items={breadcrumb} />
@@ -100,6 +106,7 @@ export default function TechniqueDetailPage({
           </div>
           <DocumentToc
             path={technique.sourcePath}
+            hideSectionSlugs={hiddenSlugs}
             extraItems={[
               ...(techniqueSpecs.length > 0 ? [{ label: "Detection spec", slug: "detection-spec" }] : []),
               ...(relatedMitigations.length > 0 ? [{ label: `Mitigations (${relatedMitigations.length})`, slug: "section-mitigations" }] : []),
@@ -140,12 +147,14 @@ export default function TechniqueDetailPage({
             )}
           </header>
 
-          {/* Full description first — primary content of the page. */}
+          {/* Full description first — primary content of the page.
+              Markdown sections we re-render as JSX cards below are hidden
+              from this body. Sections without a JSX equivalent stay. */}
           <section className="technique-detail-section technique-detail-section-description">
             <InlineMarkdown
               path={technique.sourcePath}
               onOpenDoc={onOpenDoc}
-              hideSectionSlugs={["mitigations", "real-world-examples"]}
+              hideSectionSlugs={hiddenSlugs}
             />
           </section>
 

src/components/document/DocumentToc.tsx

@@ -17,18 +17,26 @@ type TocItem = { label: string; slug: string };
 export default function DocumentToc({
   path,
   extraItems,
+  hideSectionSlugs,
 }: {
   path: string;
   extraItems?: ReadonlyArray<TocItem>;
+  // Mirror of the same prop on InlineMarkdown — slugs hidden from the
+  // rendered HTML body must also disappear from the TOC, otherwise the
+  // sidebar shows a heading whose anchor target was removed.
+  hideSectionSlugs?: ReadonlyArray<string>;
 }) {
   const indexEntry = siteData.documentIndex[path as keyof typeof siteData.documentIndex];
-  const markdownItems = (indexEntry?.toc ?? []).map((label) => ({
-    label,
-    slug: label
-      .toLowerCase()
-      .replace(/[^a-z0-9]+/g, "-")
-      .replace(/^-|-$/g, ""),
-  }));
+  const hidden = new Set(hideSectionSlugs ?? []);
+  const markdownItems = (indexEntry?.toc ?? [])
+    .map((label) => ({
+      label,
+      slug: label
+        .toLowerCase()
+        .replace(/[^a-z0-9]+/g, "-")
+        .replace(/^-|-$/g, ""),
+    }))
+    .filter((item) => !hidden.has(item.slug));
   const items: TocItem[] = [...markdownItems, ...(extraItems ?? [])];
   if (items.length === 0) return null;