Studies: Finished & archived section with Archive/Restore

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/hooks/useProjectLibrary.js

@@ -200,17 +200,16 @@ export function useProjectLibrary({
     }
   };
 
-  // Puts a study in a series ("Romans", "Advent 2026"), or takes it out (an empty name).
-  const setProjectSeries = (id, series) => {
+  // Changes one top-level field of a stored study (from Home, without opening it) and syncs it.
+  const patchStoredStudy = (id, patch) => {
     const loaded = loadProjectById(id);
     if (!loaded) return;
-    const name = String(series ?? '').trim().slice(0, 80);
-    if ((loaded.series ?? '') === name) return;
-    const updated = { ...loaded, series: name, lastEdited: Date.now() };
+    if (Object.entries(patch).every(([k, v]) => (loaded[k] ?? (typeof v === 'boolean' ? false : '')) === v)) return;
+    const updated = { ...loaded, ...patch, lastEdited: Date.now() };
     saveProjectToStorage(updated);
     unsyncedStudies.add(id);
     setProjectIndex(loadProjectIndex());
-    if (project?.id === id) setProject((current) => (current ? { ...current, series: name } : current));
+    if (project?.id === id) setProject((current) => (current ? { ...current, ...patch } : current));
     saveRemoteProject(updated, { baseEdited: getSyncBase(id) }).then((result) => {
       if (result.ok) {
         const serverEdited = result.data?.lastEdited ?? updated.lastEdited;
@@ -221,6 +220,12 @@ export function useProjectLibrary({
     });
   };
 
+  // Puts a study in a series ("Romans", "Advent 2026"), or takes it out (an empty name).
+  const setProjectSeries = (id, series) => patchStoredStudy(id, { series: String(series ?? '').trim().slice(0, 80) });
+
+  // Moves a study to (or back from) the "Finished & archived" section on Home.
+  const setProjectArchived = (id, archived) => patchStoredStudy(id, { archived: !!archived });
+
   // Changes one chunk of a stored study (from Home, without opening it) and syncs it. `change` takes the chunk, returns the new one.
   const updateStoredChunk = (id, chunkId, change) => {
     const loaded = loadProjectById(id);
@@ -318,6 +323,7 @@ export function useProjectLibrary({
     openStudyChunk,
     renameProjectInStorage,
     setProjectSeries,
+    setProjectArchived,
     saveChunkRecall,
     saveChunkPatch,
     deleteProject,