Set up auto metric collection

Add Django Celery tasks and utilities to periodically collect system metrics (error rates, response times, queue sizes) and record them into metric_time_series. Include monitoring app scaffolding, metrics collector, Celery beat schedule, middleware for live metrics, and a Supabase edge function for cross-source metrics.

django/apps/monitoring/middleware.py

@@ -0,0 +1,52 @@
+"""
+Middleware for tracking API response times and error rates.
+"""
+import time
+import logging
+from django.core.cache import cache
+from django.utils.deprecation import MiddlewareMixin
+
+logger = logging.getLogger(__name__)
+
+
+class MetricsMiddleware(MiddlewareMixin):
+    """
+    Middleware to track API response times and error rates.
+    Stores metrics in cache for periodic collection.
+    """
+    
+    def process_request(self, request):
+        """Record request start time."""
+        request._metrics_start_time = time.time()
+        return None
+    
+    def process_response(self, request, response):
+        """Record response time and update metrics."""
+        if hasattr(request, '_metrics_start_time'):
+            response_time = (time.time() - request._metrics_start_time) * 1000  # Convert to ms
+            
+            # Store response time in cache for aggregation
+            cache_key = 'metrics:response_times'
+            response_times = cache.get(cache_key, [])
+            response_times.append(response_time)
+            
+            # Keep only last 100 response times
+            if len(response_times) > 100:
+                response_times = response_times[-100:]
+            
+            cache.set(cache_key, response_times, 300)  # 5 minute TTL
+            
+            # Track cache hits/misses
+            if response.status_code == 200:
+                cache.incr('metrics:cache_hits', 1)
+            
+        return response
+    
+    def process_exception(self, request, exception):
+        """Track exceptions and error rates."""
+        logger.error(f"Exception in request: {exception}", exc_info=True)
+        
+        # Increment error counter
+        cache.incr('metrics:cache_misses', 1)
+        
+        return None