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/epic0/0.2-configuration-management-system.md

@@ -125,16 +125,16 @@ logging:
    - Test injection
 
 ## Acceptance Criteria
-- [ ] `ConfigProvider` interface is defined and documented
-- [ ] Viper implementation loads YAML files successfully
-- [ ] Environment variables override YAML values
-- [ ] Type-safe getters work correctly (string, int, bool, etc.)
-- [ ] Configuration can be unmarshaled into structs
-- [ ] Nested keys work with dot notation
-- [ ] Configuration system is injectable via DI container
-- [ ] All modules can access configuration through interface
-- [ ] Configuration validation works
-- [ ] Error handling is comprehensive
+- [x] `ConfigProvider` interface is defined and documented
+- [x] Viper implementation loads YAML files successfully
+- [x] Environment variables override YAML values
+- [x] Type-safe getters work correctly (string, int, bool, etc.)
+- [x] Configuration can be unmarshaled into structs
+- [x] Nested keys work with dot notation
+- [x] Configuration system is injectable via DI container
+- [x] All modules can access configuration through interface
+- [x] Configuration validation works
+- [x] Error handling is comprehensive
 
 ## Related ADRs
 - [ADR-0004: Configuration Management](../../adr/0004-configuration-management.md)