Add dismiss functionality for cloud-init build status</message>

<message>Implement a new API endpoint to clear the build status to idle, allowing users to dismiss messages after a build is cancelled, completed, or errored. Update the dashboard UI to include a dismiss link that appears under relevant conditions, enhancing user experience by providing a clearer interface for managing build statuses. Modify the JavaScript to handle the dismissal action and ensure proper status updates are reflected in the UI.

emmc-provisioning/host/build-cloudinit-image.sh

@@ -190,11 +190,24 @@ mkdir -p "$OUTPUT_DIR"
 cp "$IMG_FILE" "$OUT_PATH"
 
 # Compress to .img.xz to reduce size (deploy supports decompress on the fly)
+check_cancel
 write_status "finalizing" "Compressing image (xz)…" "" ""
 OUT_XZ="${OUT_PATH}.xz"
-# -T 0 = use all cores; fallback to -T 1 if old xz
-if ! xz -T 0 -z -k -f "$OUT_PATH" 2>/dev/null; then
-    xz -T 1 -z -k -f "$OUT_PATH" 2>/dev/null || true
+xz -T 0 -z -k -f "$OUT_PATH" 2>/dev/null &
+XZ_PID=$!
+while kill -0 "$XZ_PID" 2>/dev/null; do
+  if [[ -f "$CANCEL_FILE" ]]; then
+    kill "$XZ_PID" 2>/dev/null
+    wait "$XZ_PID" 2>/dev/null
+    write_status "cancelled" "Build cancelled." "" ""
+    rm -f "$REQUEST_FILE" "$CANCEL_FILE"
+    exit 0
+  fi
+  sleep 2
+done
+wait "$XZ_PID" 2>/dev/null || true
+if [[ ! -f "$OUT_XZ" ]]; then
+  xz -T 1 -z -k -f "$OUT_PATH" 2>/dev/null || true
 fi
 if [[ -f "$OUT_XZ" ]]; then
     rm -f "$OUT_PATH"