feat: git panel redesign (#535)

* feat(git-panel): add Branches tab, Fetch always visible, inline error banners

- Add dedicated Branches tab (local/remote sections, switch with confirmation, delete branch, create branch)
- Rename History tab to Commits; add change-count badge on Changes tab
- Fetch button always visible when remote exists (not only when both ahead & behind)
- Inline error banner below header for failed push/pull/fetch, with dismiss button
- Server: /api/git/branches now returns localBranches + remoteBranches separately
- Server: add /api/git/delete-branch endpoint (prevents deleting current branch)
- Controller: expose operationError, clearOperationError, deleteBranch, localBranches, remoteBranches
- Constants: add deleteBranch to all ConfirmActionType record maps

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix: git log datetime

* feat(git-panel): add staged/unstaged sections and enhanced commit details

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Haile <118998054+blackmammoth@users.noreply.github.com>

src/components/git-panel/view/history/CommitHistoryItem.tsx

@@ -1,7 +1,16 @@
 import { ChevronDown, ChevronRight } from 'lucide-react';
+import { useMemo } from 'react';
 import type { GitCommitSummary } from '../../types/types';
+import { getStatusBadgeClass, parseCommitFiles } from '../../utils/gitPanelUtils';
 import GitDiffViewer from '../shared/GitDiffViewer';
 
+function formatDate(dateString: string): string {
+  return new Date(dateString).toLocaleDateString('en-US', {
+    year: 'numeric',
+    month: 'short',
+    day: 'numeric',
+  });
+}
 
 type CommitHistoryItemProps = {
   commit: GitCommitSummary;
@@ -20,6 +29,11 @@ export default function CommitHistoryItem({
   wrapText,
   onToggle,
 }: CommitHistoryItemProps) {
+  const fileSummary = useMemo(() => {
+    if (!diff) return null;
+    return parseCommitFiles(diff);
+  }, [diff]);
+
   return (
     <div className="border-b border-border last:border-0">
       <button
@@ -50,10 +64,83 @@ export default function CommitHistoryItem({
 
       {isExpanded && diff && (
         <div className="bg-muted/50">
-          <div className="max-h-96 overflow-y-auto p-2">
-            <div className="mb-2 font-mono text-sm text-muted-foreground">
-              {commit.stats}
+          <div className="max-h-[32rem] overflow-y-auto p-3">
+            {/* Full hash */}
+            <p className="mb-2 select-all font-mono text-xs text-muted-foreground/70">
+              {commit.hash}
+            </p>
+
+            {/* Author + Date */}
+            <div className="mb-3 flex gap-4 text-xs text-muted-foreground">
+              <span>
+                <span className="text-muted-foreground/60">Author </span>
+                {commit.author}
+              </span>
+              <span>
+                <span className="text-muted-foreground/60">Date </span>
+                {formatDate(commit.date)}
+              </span>
             </div>
+
+            {/* Stats card */}
+            {fileSummary && (
+              <div className="mb-3 flex gap-4 rounded-md bg-muted/80 px-4 py-2 text-center text-xs">
+                <div>
+                  <div className="text-muted-foreground/60">Files</div>
+                  <div className="font-semibold text-foreground">{fileSummary.totalFiles}</div>
+                </div>
+                <div>
+                  <div className="text-muted-foreground/60">Added</div>
+                  <div className="font-semibold text-green-600 dark:text-green-400">+{fileSummary.totalInsertions}</div>
+                </div>
+                <div>
+                  <div className="text-muted-foreground/60">Removed</div>
+                  <div className="font-semibold text-red-600 dark:text-red-400">-{fileSummary.totalDeletions}</div>
+                </div>
+              </div>
+            )}
+
+            {/* Changed files list */}
+            {fileSummary && fileSummary.files.length > 0 && (
+              <div className="mb-3">
+                <p className="mb-1.5 text-xs font-semibold uppercase tracking-wider text-muted-foreground/60">
+                  Changed Files
+                </p>
+                <div className="rounded-md border border-border/60">
+                  {fileSummary.files.map((file, idx) => (
+                    <div
+                      key={file.path}
+                      className={`flex items-center gap-2 px-2.5 py-1.5 text-xs ${
+                        idx < fileSummary.files.length - 1 ? 'border-b border-border/40' : ''
+                      }`}
+                    >
+                      <span
+                        className={`inline-flex h-4 w-4 flex-shrink-0 items-center justify-center rounded border text-[9px] font-bold ${getStatusBadgeClass(file.status)}`}
+                      >
+                        {file.status}
+                      </span>
+                      <span className="min-w-0 flex-1 truncate">
+                        {file.directory && (
+                          <span className="text-muted-foreground/60">{file.directory}</span>
+                        )}
+                        <span className="font-medium text-foreground">{file.filename}</span>
+                      </span>
+                      <span className="flex-shrink-0 font-mono text-muted-foreground/60">
+                        {file.insertions > 0 && (
+                          <span className="text-green-600 dark:text-green-400">+{file.insertions}</span>
+                        )}
+                        {file.insertions > 0 && file.deletions > 0 && '/'}
+                        {file.deletions > 0 && (
+                          <span className="text-red-600 dark:text-red-400">-{file.deletions}</span>
+                        )}
+                      </span>
+                    </div>
+                  ))}
+                </div>
+              </div>
+            )}
+
+            {/* Diff viewer */}
             <GitDiffViewer diff={diff} isMobile={isMobile} wrapText={wrapText} />
           </div>
         </div>