Remove all hardcoded deployment values; read from sky-cam.conf

- sunrise_video.10s.sh: use $TIMEZONE (was hardcoded America/New_York),
  $SUNRISE_PRE_MIN/$SUNRISE_POST_MIN for capture window, $SUNRISE_TARGET_SECS
  for output duration (was wrong value 8 in a script named 10s)
- fullday-video.sh: remove hardcoded FULLDAY_FPS/RETENTION_DAYS; both now
  come from sky-cam.conf
- 4-seasons.sh, montage-mvt.sh: export TIMEZONE after sourcing conf so
  season_info.py subprocess picks it up via env rather than falling back
  to its hardcoded America/New_York default
- sky-cam.conf: add SUNRISE_PRE_MIN, SUNRISE_POST_MIN, SUNRISE_TARGET_SECS,
  FULLDAY_FPS, RETENTION_DAYS

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

4-seasons.sh

@@ -12,6 +12,7 @@ set -x
 
 SCRIPT_DIR="$(dirname "$(realpath "$0")")"
 source "$SCRIPT_DIR/sky-cam.conf"
+export TIMEZONE   # make it visible to season_info.py subprocess
 
 # ── Configuration ──────────────────────────────────────────────────────────────
 base_dir="$BASE_DIR"