feat(wiki): show System as author for seeded documentation pages

Seeded Documentation pages have no lastEditor; the index cards and the detail header now read 'System' instead of 'Unknown editor' for those. Other categories keep the old fallback.

src/app/(frontend)/wiki/[slug]/page.tsx

@@ -181,7 +181,11 @@ export default async function WikiDetailPage({
         </div>
 
         <article>
-          <WikiContent prepared={prepared} scopeClasses={scopeClasses} htmlTemplates={templateHtmlMap} />
+          <WikiContent
+            prepared={prepared}
+            scopeClasses={scopeClasses}
+            htmlTemplates={templateHtmlMap}
+          />
         </article>
       </div>
     );
@@ -218,7 +222,15 @@ export default async function WikiDetailPage({
             </div>
           </div>
           <div className="flex shrink-0 flex-col items-end gap-1 text-right text-xs text-muted-foreground">
-            <span>Last edited by {relationName(page.lastEditor)}</span>
+            {/* Seeded Documentation pages are written by the system, not a user. */}
+            <span>
+              Last edited by{" "}
+              {page.lastEditor != null
+                ? relationName(page.lastEditor)
+                : page.category === "Documentation"
+                  ? "System"
+                  : "Unknown editor"}
+            </span>
             <time dateTime={page.updatedAt}>{formatDate(page.updatedAt)}</time>
           </div>
         </div>
@@ -227,7 +239,11 @@ export default async function WikiDetailPage({
       {lockdown && <LockdownBanner />}
 
       <article>
-        <WikiContent prepared={prepared} scopeClasses={scopeClasses} htmlTemplates={templateHtmlMap} />
+        <WikiContent
+          prepared={prepared}
+          scopeClasses={scopeClasses}
+          htmlTemplates={templateHtmlMap}
+        />
       </article>
 
       <WikiToolbar

src/app/(frontend)/wiki/page.tsx

@@ -46,7 +46,13 @@ export default async function WikiPage() {
     category: page.category,
     tags: page.tags ?? [],
     updatedAt: page.updatedAt,
-    lastEditorName: relationName(page.lastEditor),
+    // Seeded Documentation pages are written by the system, not a user.
+    lastEditorName:
+      page.lastEditor != null
+        ? relationName(page.lastEditor)
+        : page.category === "Documentation"
+          ? "System"
+          : "Unknown editor",
   }));
 
   return (