Consolidate config into sky-cam.conf; systemd failure notifications

sky-cam.conf (new)
- Single file replaces mattermost_config.txt reference, notify_config.txt,
  and the hardcoded BASE_DIR/MUSIC_DIR/TIMEZONE scattered across scripts
- Bash-sourceable and Python key=value readable (same format)

All .sh scripts
- source sky-cam.conf at startup; BASE_DIR / MUSIC_DIR from config

sunrise2mm.py
- Reads sky-cam.conf relative to script location; no hardcoded path

notify.sh
- Sources sky-cam.conf; Mattermost credentials come from there directly,
  no separate mattermost_config.txt lookup needed

systemd/sky-cam-notify-failure@.service (new)
- Template unit called by OnFailure= in each service
- Sends notification via notify.sh when any sky-cam job fails
- All three .service units now have OnFailure=sky-cam-notify-failure@%n.service

Removed: notify_config.txt, sky-cam.crontab (superseded)

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

sky-cam.conf

@@ -0,0 +1,33 @@
+# sky-cam.conf — single config for all sky-cam scripts and Python helpers.
+#
+# Bash scripts source this file:
+#   source "$(dirname "$(realpath "$0")")/sky-cam.conf"
+#
+# Python reads it with key=value parsing (same format, quotes stripped).
+#
+# Copy this file to your scripts directory and fill in every value.
+# Lines starting with # are comments and are ignored.
+
+# ── Paths ─────────────────────────────────────────────────────────────────────
+BASE_DIR=/home/motion/drives/local-2tb
+MUSIC_DIR=/home/motion/drives/local-2tb/music/4 Seasons
+TIMEZONE=America/New_York
+
+# ── Mattermost — daily sunrise upload ────────────────────────────────────────
+mattermost_url=https://your-mattermost-server.example.com
+access_token=your-access-token-here
+channel_id=your-daily-upload-channel-id-here
+
+# ── Notifications — movement montage + year-end video complete / job failure ──
+# ntfy: https://ntfy.sh (cloud) or self-hosted.  Set topic URL below.
+NTFY_ENABLED=false
+NTFY_URL=https://ntfy.sh/your-topic-here
+
+# Email: requires the 'mail' command (mailutils / s-nail).
+EMAIL_ENABLED=false
+EMAIL_TO=you@example.com
+EMAIL_FROM=skycam@localhost
+
+# Mattermost text post (can be same channel as daily upload or a private one).
+MM_NOTIFY_ENABLED=false
+MM_NOTIFY_CHANNEL_ID=your-notify-channel-id-here