feat: add catch-up systemd timer and runner script for main.py

Co-authored-by: aider (openai/gpt-5) <aider@aider.chat>

systemd/libguides-notifier.service

@@ -0,0 +1,14 @@
+# User-level systemd service to run main.py
+# Uses a wrapper script so the working directory and .env are found correctly.
+# Replace REPO_PATH automatically using the setup command we provide.
+[Unit]
+Description=Run main.py (LibGuides notifier)
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+Type=oneshot
+ExecStart="REPO_PATH/scripts/run_main.sh"
+
+[Install]
+WantedBy=default.target

systemd/libguides-notifier.timer

@@ -0,0 +1,17 @@
+# User-level systemd timer that "catches up" missed runs if the machine was off.
+[Unit]
+Description=Schedule main.py with catch-up if missed
+
+[Timer]
+# Change this to your desired schedule; examples:
+# OnCalendar=daily
+# OnCalendar=Mon..Fri 09:00
+# See man systemd.time for syntax.
+OnCalendar=hourly
+Persistent=true
+AccuracySec=1m
+RandomizedDelaySec=5m
+Unit=libguides-notifier.service
+
+[Install]
+WantedBy=timers.target