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/epic1/1.3-health-metrics-system.md

@@ -4,7 +4,7 @@
 - **Story ID**: 1.3
 - **Title**: Health Monitoring and Metrics System
 - **Epic**: 1 - Core Kernel & Infrastructure
-- **Status**: Pending
+- **Status**: Completed
 - **Priority**: High
 - **Estimated Time**: 5-6 hours
 - **Dependencies**: 1.1, 1.2
@@ -85,14 +85,14 @@ This story creates a complete health monitoring system with liveness and readine
    - Register in container
 
 ## Acceptance Criteria
-- [ ] `/healthz` returns 200 when service is alive
-- [ ] `/ready` checks database connectivity and returns appropriate status
-- [ ] `/metrics` exposes Prometheus metrics in correct format
-- [ ] All HTTP requests are measured
-- [ ] Database queries are instrumented
-- [ ] Metrics are registered in DI container
-- [ ] Health checks can be extended by modules
-- [ ] Metrics follow Prometheus naming conventions
+- [x] `/healthz` returns 200 when service is alive
+- [x] `/ready` checks database connectivity and returns appropriate status
+- [x] `/metrics` exposes Prometheus metrics in correct format
+- [x] All HTTP requests are measured
+- [x] Database queries are instrumented
+- [x] Metrics are registered in DI container
+- [x] Health checks can be extended by modules
+- [x] Metrics follow Prometheus naming conventions
 
 ## Related ADRs
 - [ADR-0014: Health Check Implementation](../../adr/0014-health-check-implementation.md)