chore: add env-based REPO_PATH config for libguides-notifier.service

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

systemd/libguides-notifier.service

@@ -1,11 +1,10 @@
 # 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.
-# Install step 2 does three things:
-# - Replaces REPO_PATH with your repo’s absolute path in the COPY of this unit at ~/.config/systemd/user/
-#   so ExecStart points to the correct scripts/run_main.sh.
-# - Marks scripts/run_main.sh as executable (chmod +x).
-# - Reloads user units (systemctl --user daemon-reload) so systemd picks up the updated service/timer.
+# Configuration is via ~/.config/libguides-notifier.env, no in-file path edits needed.
+# Create that file with one line:
+#   REPO_PATH=/absolute/path/to/this/repo
+# Then run:
+#   systemctl --user daemon-reload
 [Unit]
 Description=Run main.py (LibGuides notifier)
 Wants=network-online.target
@@ -13,7 +12,8 @@ After=network-online.target
 
 [Service]
 Type=oneshot
-ExecStart="REPO_PATH/scripts/run_main.sh"
+EnvironmentFile=%h/.config/libguides-notifier.env
+ExecStart="${REPO_PATH}/scripts/run_main.sh"
 
 [Install]
 WantedBy=default.target