Persist spans to DB via logger

Implement fire-and-forget span persistence:
- Add logSpanToDatabase and persistSpanToDatabase to logger
- Persist spans, attributes, events, and event attributes to new tables
- Wire edgeFunctionWrapper to call DB persistence after each span
- Create required tables, views, and security policies
- Ensure non-blocking and guard for missing Supabase creds

supabase/migrations/20251111042659_2691087d-ffdb-4d70-a35b-17cfc8ecc279.sql

@@ -0,0 +1,80 @@
+-- Fix security warnings from span storage schema
+
+-- Drop and recreate views with SECURITY INVOKER
+DROP VIEW IF EXISTS public.trace_summary;
+DROP VIEW IF EXISTS public.span_hierarchy;
+
+-- Recreate trace_summary with SECURITY INVOKER
+CREATE VIEW public.trace_summary
+WITH (security_invoker = true)
+AS
+SELECT
+  trace_id,
+  COUNT(*) as span_count,
+  MIN(start_time) as trace_start,
+  MAX(end_time) as trace_end,
+  SUM(duration_ms) as total_duration_ms,
+  COUNT(*) FILTER (WHERE status = 'error') as error_count,
+  ARRAY_AGG(DISTINCT name) as span_names,
+  ARRAY_AGG(span_id ORDER BY start_time) as span_ids
+FROM public.request_spans
+GROUP BY trace_id;
+
+-- Recreate span_hierarchy with SECURITY INVOKER
+CREATE VIEW public.span_hierarchy
+WITH (security_invoker = true)
+AS
+WITH RECURSIVE span_tree AS (
+  -- Root spans (no parent)
+  SELECT
+    span_id,
+    parent_span_id,
+    trace_id,
+    name,
+    kind,
+    start_time,
+    duration_ms,
+    status,
+    1 as depth,
+    ARRAY[span_id] as path
+  FROM public.request_spans
+  WHERE parent_span_id IS NULL
+  
+  UNION ALL
+  
+  -- Child spans
+  SELECT
+    rs.span_id,
+    rs.parent_span_id,
+    rs.trace_id,
+    rs.name,
+    rs.kind,
+    rs.start_time,
+    rs.duration_ms,
+    rs.status,
+    st.depth + 1,
+    st.path || rs.span_id
+  FROM public.request_spans rs
+  INNER JOIN span_tree st ON rs.parent_span_id = st.span_id
+)
+SELECT * FROM span_tree;
+
+-- Recreate function with explicit search_path
+CREATE OR REPLACE FUNCTION public.cleanup_old_spans()
+RETURNS integer
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+DECLARE
+  deleted_count integer;
+BEGIN
+  -- Delete spans older than 30 days
+  DELETE FROM public.request_spans
+  WHERE created_at < now() - interval '30 days';
+  
+  GET DIAGNOSTICS deleted_count = ROW_COUNT;
+  
+  RETURN deleted_count;
+END;
+$$;