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/epic0/README.md

@@ -44,3 +44,7 @@ Initialize repository structure with proper Go project layout, implement configu
 - Config loads from `config/default.yaml`
 - Logger can be injected and used
 - Application starts and shuts down gracefully
+
+## Implementation Summary
+
+- [Implementation Summary and Verification Instructions](./SUMMARY.md) - Complete guide on how to verify all Epic 0 functionality