scraper: remove dead InstanceTracker class

scraper.py

@@ -25,50 +25,6 @@ if os.path.exists('searx.instances'):
                           if line.lower().startswith('http')]
 
 
-class InstanceTracker(object):
-    """Track instance health with exponential backoff."""
-
-    def __init__(self, instances, base_delay=30, max_delay=3600):
-        self.instances = list(instances)
-        self.base_delay = base_delay
-        self.max_delay = max_delay
-        self.failures = {}
-        self.backoff_until = {}
-        self.success_count = {}
-
-    def get_available(self):
-        """Return instances not currently in backoff."""
-        now = time.time()
-        available = []
-        for inst in self.instances:
-            if inst not in self.backoff_until or now >= self.backoff_until[inst]:
-                available.append(inst)
-        return available
-
-    def mark_success(self, instance):
-        """Reset failure count on success."""
-        self.failures[instance] = 0
-        self.success_count[instance] = self.success_count.get(instance, 0) + 1
-        if instance in self.backoff_until:
-            del self.backoff_until[instance]
-
-    def mark_failure(self, instance):
-        """Increment failure count and set exponential backoff."""
-        count = self.failures.get(instance, 0) + 1
-        self.failures[instance] = count
-        delay = min(self.base_delay * (2 ** (count - 1)), self.max_delay)
-        self.backoff_until[instance] = time.time() + delay
-        name = instance.split('/')[2] if '/' in instance else instance
-        _log('%s: backoff %ds (failures: %d)' % (name, delay, count), 'rate')
-        return delay
-
-    def get_status(self):
-        """Return status summary."""
-        available = len(self.get_available())
-        in_backoff = len(self.instances) - available
-        return available, in_backoff, len(self.instances)
-
-
 class EngineTracker(object):
     """Track multiple search engine instances with rate limiting."""