Improve CORS handling and error logging to fix moderation edge cases:
- Add x-idempotency-key to allowed CORS headers and expose explicit POST methods
- Extend CORS headers to include Access-Control-Allow-Methods
- Update edge function tracing and client error handling to better detect and log CORS/network issues
- Enhance error handling utilities to surface CORS-related failures and provide clearer user messages
Integrate Lovable Cloud tracing updates by enabling distributed tracing in edge functions, adjusting breadcrumb/trace propagation, and preparing RPC span handling. Files touched include edgeFunctionTracking and related RPC tracing scaffolding.
Implement distributed tracing across edge functions:
- Introduce span types and utilities (logger.ts enhancements)
- Replace request tracking with span-based tracing in approval and rejection flows
- Propagate and manage W3C trace context in edge tracking
- Add span visualization scaffolding (spanVisualizer.ts) and admin TraceViewer UI (TraceViewer.tsx)
- Create tracing-related type definitions and support files
- Prepare RPC call logging with span context and retries
