feat(backup-monitor): add notify_backup script skeleton and test infrastructure

scripts/notify_backup.rb

@@ -0,0 +1,58 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# notify_backup — send a backup run result to the n8n backup monitor
+#
+# USAGE
+#   notify_backup.rb [options]
+#
+# REQUIRED OPTIONS
+#   --machine NAME        Identifier for this host (e.g. desktop, vps-ovh-prod-01)
+#   --destination NAME    Backup destination (e.g. synology, backblaze-b2, local)
+#   --status STATUS       Result: success | failure | skipped
+#
+# OPTIONAL OPTIONS
+#   --bytes N             Bytes transferred (raw integer; formatted to human-readable before sending)
+#   --snapshot ID         Restic snapshot ID or equivalent
+#   --log-path PATH       Path to the backup log file for this run
+#   --notes TEXT          Free-form output (restic tail, skip reason, error message, etc.)
+#
+# REQUIRED ENV VARS
+#   N8N_SWANSONCLOUD_URL                Base URL of the n8n instance (no trailing slash)
+#                                       e.g. https://n8n.swansoncloud.com
+#   N8N_SWANSONCLOUD_BACKUP_AUTH_TOKEN  Bearer token for webhook authentication
+#
+# EXIT BEHAVIOR
+#   Always exits 0. A notification failure is logged to stderr but never causes
+#   the calling backup process to fail — the backup ran; the log is the source of truth.
+#
+# ADDING A NEW BACKUP SOURCE
+#   1. Ensure the two ENV vars above are available on the new host
+#   2. Call this script at the end of the backup process with --machine, --destination, --status
+#   3. Add the {machine, destination} pair to the Set: Expected Sources node in n8n Workflow 2
+#
+# CLASSES
+#   ByteFormatter    raw integer bytes → human-readable string (e.g. "4.50 GB")
+#   PayloadBuilder   converts CLI option hash into a clean JSON-ready hash
+#   WebhookClient    sends HTTP POST with auth header; knows nothing about backup data
+#   BackupNotifier   orchestrates: build payload → send; the only public entry point
+
+require 'net/http'
+require 'json'
+require 'optparse'
+
+class ByteFormatter
+end
+
+class PayloadBuilder
+end
+
+class WebhookClient
+end
+
+class BackupNotifier
+end
+
+if __FILE__ == $PROGRAM_NAME
+  # CLI entry point — implemented in Task 5
+end

scripts/notify_backup_test.rb

@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'minitest/autorun'
+require_relative 'notify_backup'