Add unit tests for station service and enhance documentation

- Introduced unit tests for the station service, covering creation, updating, and archiving of stations.
- Added detailed building block view documentation outlining the architecture of the Rail Game system.
- Created runtime view documentation illustrating key user interactions and system behavior.
- Developed concepts documentation detailing domain models, architectural patterns, and security considerations.
- Updated architecture documentation to reference new detailed sections for building block and runtime views.

TODO.md

@@ -13,10 +13,11 @@
 
 - [x] Implement authentication flow (backend JWT, frontend login/register forms).
 - [x] Build map visualization integrating Leaflet with OSM tiles.
-- [ ] Define geographic bounding boxes and filtering rules for importing real-world stations from OpenStreetMap.
-- [ ] Implement an import script/CLI that pulls OSM station data and normalizes it to the PostGIS schema.
-- [ ] Expose backend CRUD endpoints for stations (create, update, archive) with validation and geometry handling.
-- [ ] Build React map tooling for manual station placement and editing, including form validation.
+- [x] Define geographic bounding boxes and filtering rules for importing real-world stations from OpenStreetMap.
+- [x] Implement an import script/CLI that pulls OSM station data and normalizes it to the PostGIS schema.
+- [x] Expose backend CRUD endpoints for stations (create, update, archive) with validation and geometry handling.
+- [ ] Build React map tooling for selecting a station.
+- [ ] Build tools for station editing, including form validation.
 - [ ] Define track selection criteria and tagging rules for harvesting OSM rail segments within target regions.
 - [ ] Extend the importer to load track geometries and associate them with existing stations.
 - [ ] Implement backend track-management APIs with length/speed validation and topology checks.
@@ -35,7 +36,7 @@
 - [x] Implement data access layer with SQLAlchemy and repository abstractions.
 - [ ] Decide on canonical fixture scope (demo geography, sample trains) and document expected dataset size.
 - [ ] Author fixture generation scripts that export JSON/GeoJSON compatible with the repository layer.
-- [ ] Create ingestion utilities to load fixtures into local and CI databases.
+- [x] Create ingestion utilities to load fixtures into local and CI databases.
 - [ ] Provision a Redis instance/container for local development.
 - [ ] Add caching abstractions in backend services (e.g., network snapshot, map layers).
 - [ ] Implement cache invalidation hooks tied to repository mutations.