Fix bugs found in post-refactor audit

- verify-mvt.sh: remove dead first _info= line (used MVT_START before
  defined); fix JPEG size loop to accumulate bytes correctly and display
  human-readable total; show size in delete confirmation
- montage-mvt.sh: grep -c uses || echo 0 instead of || true to be
  unambiguous about the no-match value under set -e
- capture.sh, capture-watchdog.sh: require camera name arg, remove
  silent SUNRISE_CAM fallback
- migrate-seasons.sh: require --cam arg, error if missing
- README.md, sky-cam.conf: remove stale fullday-video.sh references;
  README pipeline diagram updated to show verify-mvt.sh

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

capture-watchdog.sh

@@ -12,7 +12,11 @@ SCRIPT_DIR="$(dirname "$(realpath "$0")")"
 source "$SCRIPT_DIR/sky-cam.conf"
 export TZ="$TIMEZONE"
 
-CAM="${1:-$SUNRISE_CAM}"
+CAM="${1:-}"
+if [ -z "$CAM" ]; then
+    echo "Usage: $0 <camera-name>"
+    exit 1
+fi
 STALE_SECS="${CAPTURE_STALE_SECS:-30}"
 CHECK_INTERVAL=$(( STALE_SECS / 3 ))
 [ "$CHECK_INTERVAL" -lt 5 ] && CHECK_INTERVAL=5