agent: Download and archive installation logs in gather.sh

Integrate the --download-logs mode into the artifact collection
process. When running in ISO_NO_REGISTRY boot mode, gather.sh now:
- Invokes the UI installer with --download-logs flag
- Includes the downloaded installation-logs.tar in the screenshot
  archive if available

The log download is best-effort and uses || true to ensure gather.sh
continues successfully even if the download fails (e.g., if the UI is
not accessible or logs are not yet available).

Installation logs are now collected alongside screenshots in the
agent-gather-console-screenshots.tar.xz archive, providing a complete
set of console artifacts for debugging.

Assisted-by: Claude Code

Author: zaneb

agent/gather.sh

@@ -5,6 +5,7 @@ set -euxo pipefail
 SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )/.." && pwd )"
 
 source "$SCRIPTDIR"/common.sh
+source "$SCRIPTDIR"/agent/common.sh
 
 while read -r line
 do
@@ -28,6 +29,17 @@ if [[ "$num_screenshots" -gt 0 ]]; then
     archive_name="agent-gather-console-screenshots.tar.xz"
     echo "Gathering screenshots to $archive_name"
 
+    # Attempt to download installation logs from the UI
+    if [[ "${AGENT_E2E_TEST_BOOT_MODE}" == "ISO_NO_REGISTRY" ]]; then
+        echo "Attempting to download installation logs from Assisted Installer UI"
+        rendezvousIP=$(getRendezvousIP)
+        ocp_dir_abs_path="$(realpath "${OCP_DIR}")"
+
+        pushd agent/isobuilder/ui_driven_cluster_installation
+        RENDEZVOUS_IP=$rendezvousIP OCP_DIR=$ocp_dir_abs_path go run main.go --download-logs || true
+        popd
+    fi
+
     # Build list of files to archive
     files_to_archive=()
 
@@ -39,6 +51,11 @@ if [[ "$num_screenshots" -gt 0 ]]; then
         files_to_archive+=("${OCP_DIR}"/*.png)
     fi
 
+    # Include installation logs if available
+    if [[ -f "${OCP_DIR}/installation-logs.tar" ]]; then
+        files_to_archive+=("${OCP_DIR}/installation-logs.tar")
+    fi
+
     # Create archive with all collected files
     tar -cJf $archive_name "${files_to_archive[@]}"
 else