add configurable thread scaling and queue counter reset

- Add scale_cooldown and scale_threshold config options
- ThreadScaler now reads scaling params from config
- Reset priority queue counter when queue empties to prevent unbounded growth

config.ini.sample

@@ -67,6 +67,10 @@ source_file = servers.txt
 # Enable Tor circuit health monitoring
 tor_safeguard = 1
 
+# Thread scaling
+scale_cooldown = 10
+scale_threshold = 10.0
+
 # Debug output
 debug = 0
 
@@ -95,6 +99,10 @@ max_fail = 5
 # Only extract URLs from same domain
 extract_samedomain = 0
 
+# Max age in days for proxy list URLs
+# URLs older than this that never produced proxies are skipped
+list_max_age_days = 7
+
 # Debug output
 debug = 0
 
@@ -140,3 +148,15 @@ listenip = 127.0.0.1
 
 # Listen port
 port = 8081
+
+[worker]
+# Distributed worker settings (for --worker mode)
+
+# Proxies per work batch
+batch_size = 100
+
+# Heartbeat interval in seconds
+heartbeat = 60
+
+# Seconds before unclaimed work is released
+claim_timeout = 300