The getGitlabBranches function was only returning the first 20 branches

due to GitLab's default API pagination limit. This prevented users from
accessing branches in repositories with more than 20 branches.

Changes:
- Add pagination loop to fetch all branches across multiple pages
- Set per_page to 100 (GitLab's maximum) for efficiency
- Add safety check using x-total header to prevent unnecessary requests
- Follow the same pagination pattern as validateGitlabProvider function

Fixes issue where branch selection was limited to first 20 branches
in repositories with many branches.

packages/server/src/utils/providers/gitlab.ts

@@ -303,22 +303,41 @@ export const getGitlabBranches = async (input: {
 
 	const gitlabProvider = await findGitlabById(input.gitlabId);
 
-	const branchesResponse = await fetch(
-		`https://gitlab.com/api/v4/projects/${input.id}/repository/branches`,
-		{
-			headers: {
-				Authorization: `Bearer ${gitlabProvider.accessToken}`,
-			},
-		},
-	);
+	const allBranches = [];
+	let page = 1;
+	const perPage = 100; // GitLab's max per page is 100
 
-	if (!branchesResponse.ok) {
-		throw new Error(`Failed to fetch branches: ${branchesResponse.statusText}`);
+	while (true) {
+		const branchesResponse = await fetch(
+			`https://gitlab.com/api/v4/projects/${input.id}/repository/branches?page=${page}&per_page=${perPage}`,
+			{
+				headers: {
+					Authorization: `Bearer ${gitlabProvider.accessToken}`,
+				},
+			},
+		);
+
+		if (!branchesResponse.ok) {
+			throw new Error(`Failed to fetch branches: ${branchesResponse.statusText}`);
+		}
+
+		const branches = await branchesResponse.json();
+
+		if (branches.length === 0) {
+			break;
+		}
+
+		allBranches.push(...branches);
+		page++;
+
+		// Check if we've reached the total using headers (optional optimization)
+		const total = branchesResponse.headers.get("x-total");
+		if (total && allBranches.length >= Number.parseInt(total)) {
+			break;
+		}
 	}
 
-	const branches = await branchesResponse.json();
-
-	return branches as {
+	return allBranches as {
 		id: string;
 		name: string;
 		commit: {