fix: single-quote awk program in stuck_procs() collector

The awk program was double-quoted inside the single-quoted
COLLECTOR_SCRIPT, causing $1/$2/$3 to be expanded by the remote
shell as empty positional parameters instead of awk field references.
This made the D-state process filter silently match nothing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

monitoring/scripts/homelab-audit.sh

@@ -79,7 +79,7 @@ zombie_count() {
 
 stuck_procs() {
   ps -eo stat=,pcpu=,comm= | \
-    awk -v t="$STUCK_PROC_CPU_WARN" "$1 ~ /^D/ && $2+0 >= t+0 {print $3}" | \
+    awk -v t="$STUCK_PROC_CPU_WARN" '\''$1 ~ /^D/ && $2+0 >= t+0 {print $3}'\'' | \
     paste -sd,
 }