Fix remaining ESCAPE issues in rate anomaly detector

- Added -- separator to awk commands (3 more fixes at lines 76, 101, 185)
- Total of 6 ESCAPE fixes in this file

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/rate-anomaly-detector.sh

@@ -73,7 +73,7 @@ detect_rate_anomaly() {
 
     # Cleanup old entries (keep last 60 seconds only)
     if [ -f "$rate_file" ]; then
-        awk -v cutoff="$((current_time - 60))" '$1 > cutoff' "$rate_file" > "${rate_file}.tmp" 2>/dev/null
+        awk -v cutoff="$((current_time - 60))" '$1 > cutoff' -- "$rate_file" > "${rate_file}.tmp" 2>/dev/null
         mv "${rate_file}.tmp" "$rate_file" 2>/dev/null
     fi
 
@@ -98,7 +98,7 @@ analyze_request_pattern() {
     local cutoff=$((current_time - window))
 
     # Get timestamps in window
-    local timestamps=$(awk -v cutoff="$cutoff" '$1 > cutoff {print $1}' "$rate_file" 2>/dev/null | sort -n)
+    local timestamps=$(awk -v cutoff="$cutoff" '$1 > cutoff {print $1}' -- "$rate_file" 2>/dev/null | sort -n)
     local total_count=$(echo "$timestamps" | wc -l)
 
     if [ "$total_count" -lt 5 ]; then
@@ -182,7 +182,7 @@ get_current_rate() {
 
     local current_time=$(date +%s)
     local cutoff=$((current_time - window))
-    local count=$(awk -v cutoff="$cutoff" '$1 > cutoff' "$rate_file" 2>/dev/null | wc -l)
+    local count=$(awk -v cutoff="$cutoff" '$1 > cutoff' -- "$rate_file" 2>/dev/null | wc -l)
 
     # Calculate requests per second
     local rate=$((count / window))