feat(ui): Listen und Ordner in einer gemischten Sidebar-Reihenfolge

Die oberste Sidebar-Ebene ist jetzt eine gemischte TopLevel-Collection, so
dass eine Liste auch oberhalb eines Ordners stehen kann. DropAsync deckt
alle vier Quelle/Ziel-Kombinationen ab, ReorderSidebarAsync numeriert die
gesamte sichtbare Reihenfolge ueber lists und list_folders hinweg.

src/ClaudeDo.Data/CLAUDE.md

@@ -67,7 +67,8 @@ All use EF Core LINQ via `ClaudeDoDbContext`. The atomic `Queued → Running` cl
 Worker's `QueuePicker` (`FromSqlRaw`), **not** here.
 
 - **TaskRepository** — CRUD, planning helpers (`CreateChildAsync`, `SetPlanningStartedAsync`, `DiscardPlanningAsync`, `UpdateChildAsync`), `UpdateAgentSettingsAsync`. ⚠️ Status-mutation primitives (`MarkRunningAsync`/`MarkDoneAsync`/`MarkFailedAsync`/`FlipAllRunningToFailedAsync`) are **`internal`** — only the Worker's `TaskStateService` may call them. `CreateChildAsync` produces children with `Status=Idle, PlanningPhase=None`. **Task-number allocation:** `AddAsync` (line 20) and `CreateChildAsync` (line 276) are the two sole task-creation paths; both call `TaskNumberAllocator.AddWithNumberAsync` to allocate a number atomically during the same transaction as the insert. Every other creation path (UI, MCP `add_task`, `batch_add_tasks`, Online Inbox sync, merge-helper handler tasks, planning children) routes through one of these two.
-- **ListRepository** — CRUD, `GetConfigAsync`/`SetConfigAsync` (upsert)/`DeleteConfigAsync` for `list_config`, plus the `list_folders` set: `GetFoldersAsync`, `AddFolderAsync` (appends, `SortOrder = COUNT(*)`), `RenameFolderAsync`, `DeleteFolderAsync` (folder only — the FK releases its lists), `SetFolderCollapsedAsync`, `SetListFolderAsync`. The folder writers are `ExecuteUpdate` patches, not entity `Update()`s, so a rename can't reset `SortOrder`/`IsCollapsed` the way `SetConfigAsync`'s verbatim copy resets forgotten columns.
+- **ListRepository** — CRUD, `GetConfigAsync`/`SetConfigAsync` (upsert)/`DeleteConfigAsync` for `list_config`, plus the `list_folders` set: `GetFoldersAsync`, `AddFolderAsync` (appends), `RenameFolderAsync`, `DeleteFolderAsync` (folder only — the FK releases its lists), `SetFolderCollapsedAsync`, `SetListFolderAsync`. The folder writers are `ExecuteUpdate` patches, not entity `Update()`s, so a rename can't reset `SortOrder`/`IsCollapsed` the way `SetConfigAsync`'s verbatim copy resets forgotten columns.
+  - ⚠️ **`lists.sort_order` and `list_folders.sort_order` share one number space** — the sidebar interleaves folders and top-level lists in a single order, so `ReorderSidebarAsync` numbers the whole visual sequence (each folder followed by its children) across both tables, and `AddAsync`/`AddFolderAsync` append via `MAX(sort_order)+1` over **both**. Never renumber one table on its own.
 - **WorktreeRepository** — CRUD, `UpdateHeadAsync`, `SetStateAsync`, `SetMergedAsync` (atomically sets State=Merged **and** stamps MergeCommit in one update — the only writer of MergeCommit)
 - **TaskAttachmentRepository** — `AddAsync`, `UpdateAsync`, `GetAsync(taskId, fileName)`, `ListByTaskIdAsync`, `DeleteAsync(taskId, fileName)`. Bulk delete-per-task is the `ON DELETE CASCADE` on `task_attachments`, not a repository method.
 - **DailyNoteRepository**, **WeekReportRepository**, **TaskRunRepository**, **SubtaskRepository**, **AppSettingsRepository**

src/ClaudeDo.Data/Repositories/ListRepository.cs

@@ -17,10 +17,20 @@ public sealed class ListRepository
     public async Task AddAsync(ListEntity entity, CancellationToken ct = default)
     {
         NormalizeWorkingDir(entity);
+        if (entity.SortOrder == 0) entity.SortOrder = await NextSortOrderAsync(ct);
         _context.Lists.Add(entity);
         await _context.SaveChangesAsync(ct);
     }
 
+    /// <summary>One past the highest <c>sort_order</c> in use — across <b>both</b> tables, because
+    /// the sidebar interleaves folders and top-level lists in a single order sequence.</summary>
+    private async Task<int> NextSortOrderAsync(CancellationToken ct = default)
+    {
+        var maxList = await _context.Lists.MaxAsync(l => (int?)l.SortOrder, ct) ?? -1;
+        var maxFolder = await _context.ListFolders.MaxAsync(f => (int?)f.SortOrder, ct) ?? -1;
+        return Math.Max(maxList, maxFolder) + 1;
+    }
+
     public async Task UpdateAsync(ListEntity entity, CancellationToken ct = default)
     {
         NormalizeWorkingDir(entity);
@@ -56,14 +66,27 @@ public sealed class ListRepository
         return await _context.Lists.OrderBy(l => l.SortOrder).ThenBy(l => l.CreatedAt).ToListAsync(ct);
     }
 
-    public async Task ReorderAsync(IReadOnlyList<string> orderedListIds, CancellationToken ct = default)
+    /// <summary>
+    /// Writes the sidebar's visual order as one sequence spanning both tables: folders and lists
+    /// share the <c>sort_order</c> number space, which is what lets a top-level list sit between
+    /// two folders. A folder's own children follow it in the sequence, so ordering folders by
+    /// <c>sort_order</c> and lists by <c>sort_order</c> independently still reproduces the sidebar.
+    /// </summary>
+    public async Task ReorderSidebarAsync(IReadOnlyList<(string Id, bool IsFolder)> ordered, CancellationToken ct = default)
     {
-        var idSet = orderedListIds.ToHashSet();
-        var entities = await _context.Lists.Where(l => idSet.Contains(l.Id)).ToListAsync(ct);
-        for (int i = 0; i < orderedListIds.Count; i++)
+        var listIds = ordered.Where(o => !o.IsFolder).Select(o => o.Id).ToHashSet();
+        var folderIds = ordered.Where(o => o.IsFolder).Select(o => o.Id).ToHashSet();
+        var lists = await _context.Lists.Where(l => listIds.Contains(l.Id)).ToListAsync(ct);
+        var folders = await _context.ListFolders.Where(f => folderIds.Contains(f.Id)).ToListAsync(ct);
+
+        for (int i = 0; i < ordered.Count; i++)
         {
-            var e = entities.FirstOrDefault(x => x.Id == orderedListIds[i]);
-            if (e is not null) e.SortOrder = i;
+            var (id, isFolder) = ordered[i];
+            if (isFolder)
+            {
+                if (folders.FirstOrDefault(f => f.Id == id) is { } folder) folder.SortOrder = i;
+            }
+            else if (lists.FirstOrDefault(l => l.Id == id) is { } list) list.SortOrder = i;
         }
         await _context.SaveChangesAsync(ct);
     }
@@ -81,7 +104,7 @@ public sealed class ListRepository
 
     public async Task AddFolderAsync(ListFolderEntity folder, CancellationToken ct = default)
     {
-        folder.SortOrder = await _context.ListFolders.CountAsync(ct);
+        folder.SortOrder = await NextSortOrderAsync(ct);
         _context.ListFolders.Add(folder);
         await _context.SaveChangesAsync(ct);
     }