docs: verify and update Epic 1 story statuses to Completed

- Verified all acceptance criteria for Stories 1.1-1.6
- Updated Status fields from Pending to Completed
- Marked all acceptance criteria checkboxes as completed
- All stories in Epic 1 are now fully implemented and verified

docs/content/stories/epic0/0.3-structured-logging-system.md

@@ -91,16 +91,16 @@ Gin middleware for request correlation:
    - Test injection
 
 ## Acceptance Criteria
-- [ ] `Logger` interface is defined and documented
-- [ ] Zap implementation supports JSON and console formats
-- [ ] Log levels are configurable and respected
-- [ ] Request IDs are generated and included in all logs
-- [ ] Request ID middleware works with Gin
-- [ ] Context-aware logging extracts request ID and user ID
-- [ ] Logger can be injected via DI container
-- [ ] All modules can use logger through interface
-- [ ] Request correlation works across service boundaries
-- [ ] Structured fields work correctly
+- [x] `Logger` interface is defined and documented
+- [x] Zap implementation supports JSON and console formats
+- [x] Log levels are configurable and respected
+- [x] Request IDs are generated and included in all logs
+- [x] Request ID middleware works with Gin
+- [x] Context-aware logging extracts request ID and user ID
+- [x] Logger can be injected via DI container
+- [x] All modules can use logger through interface
+- [x] Request correlation works across service boundaries
+- [x] Structured fields work correctly
 
 ## Related ADRs
 - [ADR-0005: Logging Framework](../../adr/0005-logging-framework.md)