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

sky-cam.conf

@@ -96,6 +96,17 @@ LATITUDE=38.123456
 LONGITUDE=-97.654321
 TIMEZONE=America/New_York
 
+# ── Sunrise video tuning ──────────────────────────────────────────────────────
+# How many minutes before/after sunrise to include in the daily clip.
+SUNRISE_PRE_MIN=70
+SUNRISE_POST_MIN=10
+# Target duration (seconds) for the speed-adjusted sunrise video.
+SUNRISE_TARGET_SECS=10
+
+# ── Full-day timelapse tuning ─────────────────────────────────────────────────
+FULLDAY_FPS=5        # frame rate of the timelapse video
+RETENTION_DAYS=10    # delete full-day videos older than this many days
+
 # ── Mattermost — daily sunrise upload ─────────────────────────────────────────
 mattermost_url=https://your-mattermost-server.example.com
 access_token=your-access-token-here