fix(linux_configuration): sync music_parallelism.sh from live and detoxify organize_downloads.sh

- music_parallelism.sh: restore batched-pgrep/xdotool optimization that exists
  in /usr/local/bin/ but had been lost from the repo, plus bump intervals
  (FAST 0.5s->2s, IDLE 3s->10s) to further cut fork rate
- organize_downloads.sh: replace per-file tr fork with bash 4 ${var,,}
  parameter expansion, replace per-log-line $(date) fork with printf %()T builtin

Follow-up to fork-storm fixes after observing 122 CPU-hours of date calls
in a 90-minute window (root cause was nvidia-pmon-logger.sh, fixed separately).

linux_configuration/scripts/digital_wellbeing/music_parallelism.sh

@@ -27,7 +27,8 @@ LOG_DIR="${XDG_STATE_HOME:-$HOME/.local/state}/music-parallelism"
 mkdir -p "$LOG_DIR" 2> /dev/null || true
 export LOG_FILE="$LOG_DIR/music-parallelism.log"
 CHECK_INTERVAL=3
-FAST_CHECK_INTERVAL=0.5
+FAST_CHECK_INTERVAL=2
+IDLE_CHECK_INTERVAL=10
 
 # Override focus apps with extended list for this script
 FOCUS_APPS_WINDOWS=(
@@ -223,7 +224,7 @@ instant_monitor_loop() {
       sleep "$FAST_CHECK_INTERVAL"  # High-frequency check while focus app is active
     else
       # No focus app detected: use longer sleep to reduce fork overhead significantly
-      sleep 3
+      sleep "$IDLE_CHECK_INTERVAL"
     fi
   done
 }

linux_configuration/scripts/utils/organize_downloads.sh

@@ -37,9 +37,11 @@ TEMP_DIR="${XDG_CACHE_HOME:-$HOME/.cache}/media_organize_$$"
 IMAGE_EXTENSIONS=("jpg" "jpeg" "png" "gif" "bmp" "tiff" "tif" "webp" "raw" "cr2" "nef" "orf" "arw" "dng" "heic" "heif")
 VIDEO_EXTENSIONS=("mp4" "avi" "mkv" "mov" "wmv" "flv" "webm" "m4v" "3gp" "ogv" "mpg" "mpeg" "mts" "m2ts" "vob")
 
-# Function to log messages with timestamp
+# Function to log messages with timestamp (bash builtin %()T = zero forks)
 log() {
-	echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1"
+	local ts
+	printf -v ts '%(%Y-%m-%d %H:%M:%S)T' -1
+	echo "[$ts] $1"
 }
 
 # Parse CLI flags early
@@ -65,11 +67,11 @@ while [[ ${1:-} =~ ^- ]]; do
 	esac
 done
 
-# Function to check if file has media extension
+# Function to check if file has media extension (zero forks: bash 4 ${var,,})
 is_media_file() {
 	local file="$1"
 	local extension="${file##*.}"
-	extension=$(echo "$extension" | tr '[:upper:]' '[:lower:]')
+	extension="${extension,,}"
 
 	# Check if it's an image
 	for ext in "${IMAGE_EXTENSIONS[@]}"; do