fix: add pull_request_url and branch_name to CodeBuild success response

returning repository_url/repository_name, causing CFN to fail with:
  'Vendor response doesn't contain pull_request_url attribute'

After CodeBuild SUCCEEDED, query GitHub API /pulls?state=open on the
created repo to get the real PR URL and branch name.

template_automation/app.py

@@ -736,11 +736,40 @@ def lambda_handler(event: dict, context) -> dict:
                 repo_base = github_api.rstrip("/").removesuffix("/api/v3")
                 github_org = os.environ.get("GITHUB_ORG_NAME", "SCT-Engineering")
                 repo_url = f"{repo_base}/{github_org}/{cfn_input.project_name}"
+
+                # Fetch the open PR so we can return pull_request_url and branch_name
+                # (both are required by the CloudFormation template Outputs section).
+                pull_request_url = "N/A"
+                branch_name = "repo-init"
+                try:
+                    import urllib.request as _urllib
+                    api_base = github_api.rstrip("/")
+                    prs_url = f"{api_base}/repos/{github_org}/{cfn_input.project_name}/pulls?state=open"
+                    req = _urllib.Request(prs_url, headers={"Authorization": f"token {github_token}"})
+                    import ssl as _ssl
+                    ctx = _ssl.create_default_context()
+                    ctx.check_hostname = False
+                    ctx.verify_mode = _ssl.CERT_NONE
+                    with _urllib.urlopen(req, context=ctx, timeout=10) as resp:
+                        prs = json.loads(resp.read())
+                    if prs:
+                        pull_request_url = prs[0].get("html_url", "N/A")
+                        branch_name = prs[0].get("head", {}).get("ref", "repo-init")
+                        logger.info(f"[{request_id}] Found PR: {pull_request_url} (branch: {branch_name})")
+                    else:
+                        logger.warning(f"[{request_id}] No open PRs found on {cfn_input.project_name}")
+                except Exception as pr_err:
+                    logger.warning(f"[{request_id}] Could not fetch PR URL: {pr_err}")
+
                 response_data = {
                     "RepositoryUrl":    repo_url,
                     "repository_url":   repo_url,
                     "RepositoryName":   cfn_input.project_name,
                     "repository_name":  cfn_input.project_name,
+                    "PullRequestUrl":   pull_request_url,
+                    "pull_request_url": pull_request_url,
+                    "BranchName":       branch_name,
+                    "branch_name":      branch_name,
                     "CodeBuildBuildId": build_id,
                 }
                 physical_resource_id = f"{cfn_input.project_name}-repository"