Fix undefined CAM_NAME crash; log when window already closed on re-run

4-seasons.sh, fullday-video.sh: CAM_NAME fallback referenced undefined
\$CAM_NAME — under set -euo pipefail this crashes if called manually without
an argument. Changed to fall back to \$SUNRISE_CAM (matches capture.sh).

daily_sunrise_video.sh: add log message when the capture window has already
closed (manual re-run after the fact). Behaviour is unchanged — processing
proceeds immediately — but the operator now gets a clear confirmation rather
than silence.

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

4-seasons.sh

@@ -14,7 +14,7 @@ source "$SCRIPT_DIR/sky-cam.conf"
 export TIMEZONE   # make it visible to season_info.py subprocess
 
 # Camera name: first argument overrides conf (systemd passes it via ExecStart).
-CAM_NAME="${1:-$CAM_NAME}"
+CAM_NAME="${1:-$SUNRISE_CAM}"
 
 # ── Configuration ──────────────────────────────────────────────────────────────
 base_dir="$BASE_DIR"