feat: member portal Sprint 10 — Knowledge Base

- KnowledgeBoard + KnowledgeItem models + migration (DRAFT/PUBLISHED/ARCHIVED status, slug per tenant)
- KnowledgeModule: admin CRUD for boards + items (auto-slug, status workflow)
- Member endpoint GET /my/knowledge?q= — published items grouped by board, optional text search over question/answer
- /my/knowledge page: search box + collapsible boards with accordion FAQ items
- KnowledgeItem accordion + KnowledgeSearch (debounced URL-driven) client components
- Knowledge nav item; register KnowledgeModule

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/app/my/knowledge/KnowledgeItem.tsx

@@ -0,0 +1,38 @@
+'use client';
+
+import { useState } from 'react';
+
+interface Props {
+  question: string;
+  answer: string;
+  tags: string[];
+}
+
+export function KnowledgeItem({ question, answer, tags }: Props) {
+  const [open, setOpen] = useState(false);
+
+  return (
+    <div className="border-b border-gray-100 last:border-0">
+      <button
+        type="button"
+        onClick={() => setOpen((o) => !o)}
+        className="w-full flex items-center justify-between gap-3 py-3.5 text-left"
+      >
+        <span className="text-sm font-medium text-gray-900">{question}</span>
+        <span className={`text-gray-400 transition-transform shrink-0 ${open ? 'rotate-180' : ''}`}>⌄</span>
+      </button>
+      {open && (
+        <div className="pb-4">
+          <p className="text-sm text-gray-600 whitespace-pre-line leading-relaxed">{answer}</p>
+          {tags.length > 0 && (
+            <div className="flex flex-wrap gap-1.5 mt-2">
+              {tags.map((t) => (
+                <span key={t} className="text-[10px] bg-gray-100 text-gray-500 rounded-full px-2 py-0.5">{t}</span>
+              ))}
+            </div>
+          )}
+        </div>
+      )}
+    </div>
+  );
+}