Add ambient chunk as 2nd audio fallback; fix capture service exit-code bug

daily_sunrise_video.sh:
- Insert continuous ambient recording extract as 2nd fallback (after today's
  scheduled sunrise audio, before live RTSP).  Finds the chunk file in
  AUDIO_DIR/<cam>/<date>/ whose start time is the latest one at or before
  sunrise, then ffmpeg-copies SUNRISE_TARGET_SECS centred on sunrise_sec.
- Renumber remaining fallbacks: live RTSP → 3rd, yesterday → 4th, library → 5th.

sunrise-audio-capture.sh:
- Fix: retention find pipeline could exit non-zero (directory not yet created
  or permission error) and with set -euo pipefail cause the service to report
  status=1/FAILURE even after a successful capture.  Guard with [ -d ] and
  add || true so a retention failure never masks a successful recording.

https://claude.ai/code/session_01DANuzLCLhhQ7Li12RTcswY

daily_sunrise_video.sh

@@ -344,7 +344,42 @@ else
             audio_src="$cam_audio"
             echo "Audio: camera recording (centred on sunrise)"
         fi
-        # 2nd fallback: live RTSP — captures current ambient sound right now
+        # 2nd fallback: continuous ambient recording — extract the sunrise window
+        # Looks in AUDIO_DIR/<cam>/<date>/ for chunk files named HH-MM-SS[.m4a|-tag.m4a]
+        # and extracts SUNRISE_TARGET_SECS centred on sunrise_sec from the right chunk.
+        if [ -z "$audio_src" ]; then
+            _amb_dir="${AUDIO_DIR:-$BASE_DIR/audio}/$CAM_NAME/$current_date"
+            if [ -d "$_amb_dir" ]; then
+                _best_chunk=""
+                _best_sec=-1
+                while IFS= read -r _f; do
+                    _hms=$(basename "$_f" | cut -c1-8)   # first 8 chars = HH-MM-SS
+                    IFS='-' read -r _h _m _s <<< "$_hms"
+                    [[ "$_h" =~ ^[0-9]{2}$ ]] || continue
+                    _cs=$(( 10#$_h * 3600 + 10#$_m * 60 + 10#$_s ))
+                    if [ "$_cs" -le "$sunrise_sec" ] && [ "$_cs" -gt "$_best_sec" ]; then
+                        _best_chunk="$_f"; _best_sec=$_cs
+                    fi
+                done < <(find "$_amb_dir" -maxdepth 1 -name "*.m4a" 2>/dev/null | sort)
+                if [ -n "$_best_chunk" ]; then
+                    _offset=$(( sunrise_sec - _best_sec - SUNRISE_TARGET_SECS / 2 ))
+                    [ "$_offset" -lt 0 ] && _offset=0
+                    temp_live_audio=$(mktemp --suffix=.m4a)
+                    echo "Audio: extracting sunrise window from ambient chunk $(basename "$_best_chunk") at +${_offset}s..."
+                    if ffmpeg -loglevel warning \
+                        -ss "$_offset" -i "$_best_chunk" \
+                        -t "$SUNRISE_TARGET_SECS" -vn -c:a copy \
+                        -y "$temp_live_audio"; then
+                        audio_src="$temp_live_audio"
+                        echo "Audio: ambient chunk extracted OK"
+                    else
+                        rm -f "$temp_live_audio"; temp_live_audio=""
+                        echo "Audio: ambient chunk extraction failed"
+                    fi
+                fi
+            fi
+        fi
+        # 3rd fallback: live RTSP — captures current ambient sound right now
         if [ -z "$audio_src" ]; then
             _rtsp_var="CAM_RTSP_${CAM_NAME}"
             _rtsp_url="${!_rtsp_var:-}"
@@ -365,7 +400,7 @@ else
                 fi
             fi
         fi
-        # 3rd fallback: yesterday's recording
+        # 4th fallback: yesterday's recording
         if [ -z "$audio_src" ]; then
             yesterday_date=$(date -d "yesterday" +%Y-%m-%d)
             yday_audio="${AUDIO_DIR:-$BASE_DIR/audio}/sunrise/$CAM_NAME/$yesterday_date/sunrise-audio.m4a"
@@ -375,7 +410,7 @@ else
                 echo "Audio: yesterday's recording ($yesterday_date)"
             fi
         fi
-        # 4th fallback: library
+        # 5th fallback: library
         if [ -z "$audio_src" ]; then
             library_dir="$SCRIPT_DIR/sunrise-sounds"
             if [ -d "$library_dir" ]; then

sunrise-audio-capture.sh

@@ -86,11 +86,15 @@ size=$(du -h "$output" | cut -f1)
 echo "Audio capture complete: $output  (${record_dur_sec}s, $size)"
 
 # Rolling retention for sunrise audio clips
+# Guard with [ -d ] so find never exits non-zero under set -euo pipefail,
+# which would cause the service to report failure even after a clean capture.
 retain="${SUNRISE_AUDIO_RETENTION_DAYS:-7}"
 if [ "$retain" -gt 0 ]; then
     audio_root="${AUDIO_DIR:-$BASE_DIR/audio}/sunrise/$CAM"
-    deleted=$(find "$audio_root" -name "sunrise-audio.m4a" -mtime +"$retain" -print -delete 2>/dev/null | wc -l)
+    if [ -d "$audio_root" ]; then
+        deleted=$(find "$audio_root" -name "sunrise-audio.m4a" -mtime +"$retain" -print -delete 2>/dev/null | wc -l) || true
         [ "$deleted" -gt 0 ] && echo "Retention: deleted $deleted sunrise audio clip(s) older than ${retain}d" || true
     fi
+fi
 
 exit 0