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

montage-mvt.sh

@@ -133,7 +133,7 @@ ffmpeg -loglevel warning \
     -f concat -safe 0 -i "$concat_list" \
     -vf "scale=${VIDEO_W}:${VIDEO_H}:force_original_aspect_ratio=decrease,\
 pad=${VIDEO_W}:${VIDEO_H}:(ow-iw)/2:(oh-ih)/2,setsar=1" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_MONTAGE" -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_MONTAGE" -an \
     -y "$temp_concat"
 
 # ── Step 2: Speed-adjust — saved permanently so music/overlay failure is recoverable ─
@@ -146,7 +146,7 @@ sped_file="$output_dir/${MVT_START}_${SEASON}_Mvt${MVT_NUM}-Sped.mp4"
 if ! ffmpeg -loglevel warning \
     -i "$temp_concat" \
     -vf "setpts=PTS/$speed_factor" \
-    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_MONTAGE" -an \
+    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_MONTAGE" -an \
     -t "$music_duration" -y "$sped_file"; then
     rm -f "$sped_file"
     "$SCRIPT_DIR/notify.sh" "FAILED: montage step 2/3 (speed) $SEASON Mvt$MVT_NUM ($ASTRO_YEAR)" \
@@ -198,7 +198,8 @@ if ffmpeg -loglevel warning \
 "[0:v]fade=t=in:st=0:d=${FADE_DUR},fade=t=out:st=${fade_out_start}:d=${FADE_DUR},${DT}[vout];\
 [1:a]afade=t=in:st=0:d=${FADE_DUR},afade=t=out:st=${fade_out_start}:d=${FADE_DUR}[aout]" \
     -map "[vout]" -map "[aout]" \
-    -c:v libx264 -pix_fmt yuv420p -c:a aac -b:a "$AUDIO_BITRATE" \
+    -c:v libx265 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_MONTAGE_FINAL" \
+    -tag:v hvc1 -c:a aac -b:a "$AUDIO_BITRATE" \
     -t "$music_duration" -y "$output_file"; then
     rm -f "$sped_file"
     echo "Done: $output_file"