feat: defer remote branch creation until first commit (#244)

* feat: defer remote branch creation until first commit

- For commit signing: branches are created remotely by github-file-ops-server on first commit
- For non-signing: branches are created locally with 'git checkout -b' and pushed when needed
- Consolidated duplicate branch creation logic in github-file-ops-server into a shared helper function
- Claude is unaware of these implementation details and simply sees it's on the correct branch
- No branch links are shown in initial comments since branches don't exist remotely yet

* fix: prevent broken branch links in final comment update

- Check if branch exists remotely before adding branch link
- Only add branch links for branches that actually exist on GitHub
- Add test coverage for non-existent remote branches
- Fixes issue where users would see broken branch links for local-only branches

* fix: don't show branch name in comment header when branch doesn't exist remotely

- Only pass branchName to updateCommentBody when branchLink exists
- Prevents showing branch names for branches that only exist locally
- Add test to verify branch name is not shown when branch doesn't exist

* tmp

test/branch-cleanup.test.ts

@@ -21,6 +21,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
   const createMockOctokit = (
     compareResponse?: any,
     deleteRefError?: Error,
+    branchExists: boolean = true,
   ): Octokits => {
     return {
       rest: {
@@ -28,6 +29,14 @@ describe("checkAndCommitOrDeleteBranch", () => {
           compareCommitsWithBasehead: async () => ({
             data: compareResponse || { total_commits: 0 },
           }),
+          getBranch: async () => {
+            if (!branchExists) {
+              const error: any = new Error("Not Found");
+              error.status = 404;
+              throw error;
+            }
+            return { data: {} };
+          },
         },
         git: {
           deleteRef: async () => {
@@ -102,6 +111,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
           compareCommitsWithBasehead: async () => {
             throw new Error("API error");
           },
+          getBranch: async () => ({ data: {} }), // Branch exists
         },
         git: {
           deleteRef: async () => ({ data: {} }),
@@ -123,7 +133,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
       `\n[View branch](${GITHUB_SERVER_URL}/owner/repo/tree/claude/issue-123-20240101_123456)`,
     );
     expect(consoleErrorSpy).toHaveBeenCalledWith(
-      "Error checking for commits on Claude branch:",
+      "Error comparing commits on Claude branch:",
       expect.any(Error),
     );
   });
@@ -148,4 +158,30 @@ describe("checkAndCommitOrDeleteBranch", () => {
       deleteError,
     );
   });
+
+  test("should return no branch link when branch doesn't exist remotely", async () => {
+    const mockOctokit = createMockOctokit(
+      { total_commits: 0 },
+      undefined,
+      false, // branch doesn't exist
+    );
+
+    const result = await checkAndCommitOrDeleteBranch(
+      mockOctokit,
+      "owner",
+      "repo",
+      "claude/issue-123-20240101_123456",
+      "main",
+      false,
+    );
+
+    expect(result.shouldDeleteBranch).toBe(false);
+    expect(result.branchLink).toBe("");
+    expect(consoleLogSpy).toHaveBeenCalledWith(
+      "Branch claude/issue-123-20240101_123456 does not exist remotely",
+    );
+    expect(consoleLogSpy).toHaveBeenCalledWith(
+      "Branch claude/issue-123-20240101_123456 does not exist remotely, no branch link will be added",
+    );
+  });
 });