feat(epic1): complete OpenTelemetry integration and add verification documentation

Story 1.6: OpenTelemetry Distributed Tracing
- Implemented tracer initialization with stdout (dev) and OTLP (prod) exporters
- Added HTTP request instrumentation via Gin middleware
- Integrated trace ID correlation in structured logs
- Added tracing configuration to config files
- Registered tracer provider in DI container

Documentation and Setup:
- Created Docker Compose setup for PostgreSQL database
- Added comprehensive Epic 1 summary with verification instructions
- Added Epic 0 summary with verification instructions
- Linked summaries in documentation index and epic READMEs
- Included detailed database testing instructions
- Added Docker Compose commands and troubleshooting guide

All Epic 1 stories (1.1-1.6) are now complete. Story 1.7 depends on Epic 2.

docs/content/stories/epic1/README.md

@@ -56,3 +56,7 @@ Extend DI container to support all core services, implement database layer with
 - Panic recovery logs errors via error bus
 - Database migrations run on startup
 - HTTP requests are traced with OpenTelemetry
+
+## Implementation Summary
+
+- [Implementation Summary and Verification Instructions](./SUMMARY.md) - Complete guide on how to verify all Epic 1 functionality, including database testing and Docker Compose setup