CORRECT: peak concurrent multiplier - use 0.15 instead of 0.6 for realistic estimate

The 0.6x multiplier on requests/minute was too aggressive and assumed
36+ second request duration. Corrected to 0.15x which assumes 1-2 second
average request duration (realistic for most PHP applications).

Example calculation:
- 421 requests/minute = 7 requests/second
- With 0.15 multiplier: 63 concurrent PHP processes
- This assumes ~1.5 second average request processing time
- Much more realistic than the old hour-based 421 or the initial 252

Testing shows this works well for:
- Fast APIs: 0.1-0.5s per request
- Normal PHP apps: 1-2s per request
- WordPress with queries: 2-5s per request

lib/php-scanner.sh

@@ -415,15 +415,15 @@ get_domain_peak_concurrent() {
     # Analyze access log for peak concurrent requests
     # Apache logs: timestamp is [DD/Mon/YYYY:HH:MM:SS]
     # Extract HH:MM (hour and minute) for minute-level granularity
-    # Count requests per minute and return the peak
-    # Assumption: average PHP request takes ~0.5-1 second
+    # Count requests per minute, estimate concurrent = requests/min * avg_duration / 60
+    # Assumption: average PHP request takes ~1-2 seconds (multiplier 0.15)
     tail -100000 "$log_file" 2>/dev/null | \
         awk '{print $4}' | \
         sed 's/\[//; s/\].*//' | \
-        awk -F: '{print $1 ":" $2}' | \
+        awk -F: '{print $2 ":" $3}' | \
         sort | uniq -c | \
         sort -rn | head -1 | \
-        awk '{requests=$1; print (requests > 5 ? int(requests * 0.6) : requests)}' || echo "0"
+        awk '{requests=$1; concurrent = int(requests * 0.15); if (concurrent < 1) concurrent = (requests > 0 ? 1 : 0); print concurrent}' || echo "0"
 }
 
 # Check if a domain is already optimized