feat: add branch listing API function

apps/web/src/api/git_repositories.ts

@@ -64,6 +64,27 @@ export async function updateRepositorySshKey(
   return response.data;
 }
 
+export interface Branch {
+  name: string;
+  is_default: boolean;
+  last_commit: string | null;
+}
+
+export interface BranchesResponse {
+  branches: Branch[];
+  default_branch: string;
+}
+
+export async function listRepositoryBranches(
+  projectId: string,
+  repoId: string
+): Promise<BranchesResponse> {
+  const response = await apiClient.get(
+    `/projects/${projectId}/repositories/${repoId}/branches`
+  );
+  return response.data;
+}
+
 export interface CommitHistoryEntry {
   hash: string;
   short_hash: string;