feat(branches): add bulk delete for branch folders

Add a context-menu action to delete all branches in a folder at once.
Top-level remote folders are protected and the currently checked-out branch
is preserved. The BranchPanel API now includes folder depth to prevent
accidental bulk-deletes and summarizes individual failures after processing.
UI polish and localization were applied, and the package/version metadata,
changelog, and help overlay were updated for the 2026.8.4 release.

- Bulk delete with top-level remote protection and failure summaries.
- BranchPanel now tracks folder depth and disables unsafe context menus.
- Version bump, changelog/help overlay updates, and UI/localization tweaks.

src/lib/components/BranchPanel.svelte

@@ -59,7 +59,7 @@
     onRenameBranch: (branch: GitBranchInfo) => void | Promise<void>;
     onDeleteBranch: (branch: GitBranchInfo) => void | Promise<void>;
     onDeleteRemoteBranch: (branch: GitBranchInfo) => void | Promise<void>;
-    onDeleteBranchFolder: (folderName: string, branches: GitBranchInfo[]) => void | Promise<void>;
+    onDeleteBranchFolder: (folderName: string, branches: GitBranchInfo[], depth: number) => void | Promise<void>;
     onCreateTag: (name: string, message: string) => void | Promise<void>;
     onDeleteTag: (tag: GitTag) => void | Promise<void>;
     onPushTag: (tag: GitTag) => void | Promise<void>;
@@ -283,7 +283,7 @@
   async function openFolderContextMenu(event: MouseEvent, folder: BranchFolderRow) {
     event.preventDefault();
     event.stopPropagation();
-    if (isBusy) return;
+    if (isBusy || (folder.depth === 0 && folder.branches.every((branch) => branch.remote))) return;
 
     contextFolder = folder;
     contextMenuX = event.clientX + 2;
@@ -324,9 +324,9 @@
 
   async function deleteContextFolder() {
     const folder = contextFolder;
-    if (!folder || isBusy) return;
+    if (!folder || isBusy || (folder.depth === 0 && folder.branches.every((branch) => branch.remote))) return;
     closeBranchContextMenu();
-    await onDeleteBranchFolder(folder.name, folder.branches);
+    await onDeleteBranchFolder(folder.name, folder.branches, folder.depth);
   }
 
   async function createContextWorktree() {
@@ -584,7 +584,7 @@
                   style={`--branch-indent: ${row.depth * 16}px;`}
                   type="button"
                   onclick={() => toggleBranchFolder(row.id)}
-                  oncontextmenu={(event) => openFolderContextMenu(event, row)}
+                  oncontextmenu={row.depth > 0 ? (event) => openFolderContextMenu(event, row) : undefined}
                   aria-expanded={isBranchFolderOpen(row.id)}
                   title={`${row.name} (${row.branchCount})`}
                 >

src/lib/components/HelpOverlay.svelte

@@ -1399,6 +1399,17 @@
     label: "Neu in Gitty",
     description: "Änderungen seit der letzten veröffentlichten Version und wichtige Neuerungen früherer Releases.",
     sections: [
+      {
+        id: "changelog-2026-8-4",
+        title: "Version 2026.8.4",
+        summary: "Dieses Release vereinfacht die Verwaltung zusammengehöriger Branches und sorgt für eine einheitlichere, klarere Oberfläche.",
+        steps: [
+          "Lokale und verschachtelte Remote-Branch-Ordner lassen sich über ihr Kontextmenü gesammelt löschen. Der oberste Remote-Ordner wie origin ist geschützt. Der aktuell ausgecheckte Branch bleibt erhalten und einzelne Fehler werden nach Abschluss verständlich aufgeführt.",
+          "Der Compare-Auswahldialog ist vollständig auf Deutsch verfügbar und orientiert sich bei Feldern, Gruppen, Typografie und Dialogflächen am Styling der externen Tools.",
+          "Die Schließen-Schaltflächen der Repository-Tabs sind quadratisch und haben ausgewogenere Abstände sowie deutlichere Hover- und Tastaturfokus-Zustände.",
+        ],
+        note: "Der oberste Remote-Ordner wie origin kann nicht gesammelt gelöscht werden. Seine Unterordner können weiterhin gezielt verwaltet werden.",
+      },
       {
         id: "changelog-2026-8-3",
         title: "Version 2026.8.3",
@@ -1488,6 +1499,17 @@
     label: "What's new",
     description: "Changes since the latest published version and notable additions from earlier releases.",
     sections: [
+      {
+        id: "changelog-2026-8-4",
+        title: "Version 2026.8.4",
+        summary: "This release simplifies managing related branches and makes the interface more consistent and easier to read.",
+        steps: [
+          "Local and nested remote branch folders can be deleted in one action from their context menu. The top-level remote folder such as origin is protected. The currently checked-out branch is kept, and individual failures are summarized after processing.",
+          "The Compare selector is fully localized in German and now follows the external-tool selectors for fields, groups, typography, and dialog surfaces.",
+          "Repository-tab close buttons are square and have more balanced spacing and clearer hover and keyboard-focus states.",
+        ],
+        note: "The top-level remote folder such as origin cannot be deleted in bulk. Its nested folders can still be managed selectively.",
+      },
       {
         id: "changelog-2026-8-3",
         title: "Version 2026.8.3",