§22 S2: collection directory at /p/<project>/ (1 → redirect, 2+ → list)

Replace DefaultCollectionRedirect with a CollectionDirectory that lists the
project's visible collections, or redirects into the sole one when there is
exactly one (preserving the S1 C3.7/C3.8 single-collection UX). The
create-first-collection empty state is S4.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/App.jsx

@@ -15,6 +15,7 @@ import RFCView from './components/RFCView.jsx'
 import PRView from './components/PRView.jsx'
 import ProposalView from './components/ProposalView.jsx'
 import ProposeModal from './components/ProposeModal.jsx'
+import CollectionDirectory from './components/CollectionDirectory.jsx'
 import ContributeRequestForm from './components/ContributeRequestForm.jsx'
 import Landing from './components/Landing.jsx'
 import Login from './components/Login.jsx'
@@ -364,9 +365,10 @@ export default function App() {
               />
               <main className="main-pane">
                 <Routes>
-                  {/* §22 three-tier (C3.7): the project landing redirects into
-                      its sole/default collection (S1: the `default` one). */}
-                  <Route path="" element={<DefaultCollectionRedirect />} />
+                  {/* §22 S2: the project landing is the collection directory —
+                      it lists collections, or (C3.7/C3.8) redirects into the
+                      sole visible collection when there is exactly one. */}
+                  <Route path="" element={<CollectionDirectoryRoute />} />
                   {/* Backcompat: the shipped v0.35.0 corpus URLs without a
                       /c/<collection>/ segment redirect into the default
                       collection, so old bookmarks keep working. */}
@@ -419,12 +421,12 @@ export default function App() {
   )
 }
 
-// §22 three-tier — corpus redirects mounted under /p/:projectId/*.
-// C3.7: the project landing skips the (single-collection) directory and lands in
-// the project's default collection.
-function DefaultCollectionRedirect() {
+// §22 S2 — the project landing at /p/:projectId/ is the collection directory.
+// A tiny wrapper reads the route's projectId and hands it to CollectionDirectory
+// (which lists collections, or redirects into the sole one — C3.7/C3.8).
+function CollectionDirectoryRoute() {
   const { projectId } = useParams()
-  return <Navigate to={`/p/${projectId}/c/${DEFAULT_COLLECTION}/`} replace />
+  return <CollectionDirectory projectId={projectId} />
 }
 
 // Backcompat for the shipped v0.35.0 corpus URLs that lacked the