Multi-camera support; schedules in conf; comment out notifications

sky-cam.conf:
- CAMERAS array replaces single CAM_NAME; add a name, add its schedules,
  re-run install.sh — no script editing needed
- SCHEDULE_SUNRISE, SCHEDULE_SEASONS_<cam>, SCHEDULE_FULLDAY_<cam> replace
  hardcoded times in install.sh
- Notification options commented out (uncomment to enable)
- Lat/lon set to mid-Atlantic (25.0, -38.0) as neutral placeholder

install.sh:
- Loops over CAMERAS to generate per-camera sky-cam-seasons-<cam> and
  sky-cam-fullday-<cam> timers with schedules from conf
- Sunrise timer remains a single sky-cam-sunrise unit (SUNRISE_CAM only)

fullday-video.sh, 4-seasons.sh, montage-mvt.sh, year-end-join.sh:
- Each accepts camera name as an argument (systemd passes it via ExecStart)
  and falls back to conf default when run manually without an arg
- Camera name propagates through the full call chain:
  4-seasons → montage-mvt → year-end-join

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

year-end-join.sh

@@ -17,9 +17,11 @@ source "$SCRIPT_DIR/sky-cam.conf"
 
 ASTRO_YEAR="${1:-}"
 if [ -z "$ASTRO_YEAR" ]; then
-    echo "Usage: $0 <ASTRO_YEAR>  (e.g. $0 2025)"
+    echo "Usage: $0 <ASTRO_YEAR> [CAM_NAME]  (e.g. $0 2025 north)"
     exit 1
 fi
+# Camera name: second argument overrides conf (passed through from montage-mvt.sh).
+CAM_NAME="${2:-$CAM_NAME}"
 
 year_dir="$BASE_DIR/movies/$CAM_NAME/$ASTRO_YEAR"