feat(masterdata): introduce Reiter-Sparte persistence, services, and validations

- Added `ReiterSparteTable` to manage rider-discipline associations.
- Introduced services and tests for `LicenseMatrix`, `Altersklasse`, and `AbteilungsRegel` with domain logic and validations for ÖTO compliance.
- Enhanced `ExposedReiterRepository` to save and query `Reiter` disciplines efficiently.
- Implemented database migration script `V007__Cleanup_Initial_Tables_and_Add_Sparte.sql`.
- Updated `MasterdataDatabaseConfiguration` to include `ReiterSparteTable` in the schema initialization.
- Expanded test coverage with new cases for eligibility checks, age group determinations, and splitting regulations.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

backend/services/masterdata/docs/ROADMAP.md

@@ -132,9 +132,9 @@
 ## Nächste konkrete Schritte (2‑Wochen Sprint‑Plan)
 
 1. [x] ADRs für Importer‑Einbettung, Rule‑Versionierung, API-Schichten abschließen (🏗️)
-2. Exposed-Tabellen vervollständigen und in `SchemaUtils.create`/Migrationen registrieren (👷)
-3. UseCases: Altersklasse, Lizenz‑Matrix, Abteilungs‑Regeln inkl. Unit‑Tests (👷🧐)
-4. ZNS‑Importer an Repositories anbinden, Idempotenz-Checks ergänzen, Mini‑ZNS Testlauf (👷🧐)
+2. [x] Exposed-Tabellen vervollständigen und in `SchemaUtils.create`/Migrationen registrieren (👷)
+3. [x] UseCases: Altersklasse, Lizenz‑Matrix, Abteilungs‑Regeln inkl. Unit‑Tests (👷🧐)
+4. [ ] ZNS‑Importer an Repositories anbinden, Idempotenz-Checks ergänzen, Mini‑ZNS Testlauf (👷🧐) *
 5. API v1 Endpunkte + OpenAPI, Contract‑Tests (👷🧐)
 6. Observability-Grundlagen (Metriken + Dashboards) (🐧)
 7. Curator: Docs aktualisieren, Runbooks und Changelogs pflegen (🧹)