Encoding: H.265 final montages, slow preset, sunrise retention

- sky-cam.conf: add ENCODE_PRESET=slow (applied to all encodes);
  split CRF_MONTAGE (intermediates, H.264) from CRF_MONTAGE_FINAL=22
  (archive montage, H.265); add SUNRISE_RETENTION_DAYS=10; improve
  CAPTURE_INTERVAL comment with storage/density table
- montage-mvt.sh: steps 1+2 use preset; step 3 final switches to
  libx265 + CRF_MONTAGE_FINAL + -tag:v hvc1 for broad compatibility
- 4-seasons.sh: both encode steps use ENCODE_PRESET
- daily_sunrise_video.sh: all encode steps use ENCODE_PRESET; rolling
  retention deletes sunrise videos older than SUNRISE_RETENTION_DAYS

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

4-seasons.sh

@@ -88,7 +88,7 @@ done > "$temp_file"
 echo "Step 1/2: encoding raw video..."
 ffmpeg -loglevel warning \
     -f concat -safe 0 -i "$temp_file" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SEASONS_RAW" -vsync 2 -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SEASONS_RAW" -vsync 2 -an \
     -y "$temp_video"
 
 raw_duration=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$temp_video")
@@ -102,7 +102,7 @@ final_file="$output_dir/${yesterday}_Mvt${MVT_NUM}-Day${DAY_OF_MVT}of${DAYS_IN_M
 if ! ffmpeg -loglevel warning \
     -i "$temp_video" \
     -vf "setpts=PTS/$speed_factor" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_SEASONS_FINAL" \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SEASONS_FINAL" \
     -t "$target_per_clip" -an \
     -y "$final_file"; then
     rm -f "$final_file"