Optimize repository loading and enhance Git UI

Consolidate multiple Git backend calls into a single bundle to reduce
overhead when opening and auto-refreshing repositories. This significantly
improves performance by fetching status, branches, commits, and files
in one optimized operation, instead of re-running 'git rev-parse' and
'git status' multiple times.

Also, streamline commit history loading by fetching file changes inline
via 'git log --name-status -z', eliminating expensive per-commit
'git diff-tree' processes.

Additionally, introduce the ability to create new branches from a
specific commit in the history and refactor the commit comparison
feature into a dedicated dialog. The status panel now displays concise
file names.

src/lib/components/StatusPanel.svelte

@@ -38,6 +38,14 @@
     return file.old_path ? `${file.old_path} -> ${file.path}` : file.path;
   }
 
+  function baseName(path: string): string {
+    return path.split(/[\\/]/).filter(Boolean).pop() ?? path;
+  }
+
+  function fileName(file: GitFileStatus): string {
+    return file.old_path ? `${baseName(file.old_path)} -> ${baseName(file.path)}` : baseName(file.path);
+  }
+
   let hasUnstaged = $derived(changedFiles.some((f) => f.unstaged !== null));
   let hasStaged = $derived(changedFiles.some((f) => f.staged !== null));
 </script>
@@ -90,7 +98,7 @@
       {#each changedFiles as file (`${file.old_path ?? ""}:${file.path}`)}
         <article class="file-row">
           <div class="file-title">
-            <strong title={displayPath(file)}>{displayPath(file)}</strong>
+            <strong title={displayPath(file)}>{fileName(file)}</strong>
           </div>
 
           <div class="change-lanes">