feat: add rename branch functionality with UI integration

packages/ui/src/lib/api/types.ts

@@ -281,6 +281,7 @@ export interface GitAPI {
   gitFetch(directory: string, options?: { remote?: string; branch?: string }): Promise<{ success: boolean }>;
   checkoutBranch(directory: string, branch: string): Promise<{ success: boolean; branch: string }>;
   createBranch(directory: string, name: string, startPoint?: string): Promise<{ success: boolean; branch: string }>;
+  renameBranch(directory: string, oldName: string, newName: string): Promise<{ success: boolean; branch: string }>;
   getGitLog(directory: string, options?: GitLogOptions): Promise<GitLogResponse>;
   getCommitFiles(directory: string, hash: string): Promise<GitCommitFilesResponse>;
   getCurrentGitIdentity(directory: string): Promise<GitIdentitySummary | null>;

packages/ui/src/lib/gitApi.ts

@@ -179,6 +179,16 @@ export async function createBranch(
   return gitHttp.createBranch(directory, name, startPoint);
 }
 
+export async function renameBranch(
+  directory: string,
+  oldName: string,
+  newName: string
+): Promise<{ success: boolean; branch: string }> {
+  const runtime = getRuntimeGit();
+  if (runtime) return runtime.renameBranch(directory, oldName, newName);
+  return gitHttp.renameBranch(directory, oldName, newName);
+}
+
 export async function getGitLog(
   directory: string,
   options: import('./api/types').GitLogOptions = {}

packages/ui/src/lib/gitApiHttp.ts

@@ -404,6 +404,23 @@ export async function createBranch(
   return response.json();
 }
 
+export async function renameBranch(
+  directory: string,
+  oldName: string,
+  newName: string
+): Promise<{ success: boolean; branch: string }> {
+  const response = await fetch(buildUrl(`${API_BASE}/branches/rename`, directory), {
+    method: 'PUT',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ oldName, newName }),
+  });
+  if (!response.ok) {
+    const error = await response.json().catch(() => ({ error: response.statusText }));
+    throw new Error(error.error || 'Failed to rename branch');
+  }
+  return response.json();
+}
+
 export async function getGitLog(
   directory: string,
   options: GitLogOptions = {}