fix(contracts) : hide contract phases entirely before RTT_START_DATE

EmployeeContractPhaseResolver now accepts the data-start date and filters
out phases whose endDate is strictly before it. No work-hour or absence
data exists before the application launch date, so legacy contract
periods that ended before that date would surface meaningless RTT/CP
figures in the phase picker.

For employees who joined long before the software (typical legacy 35h
contracts, in production since 2014), only the current phase remains
visible — which also collapses the picker (threshold ≥ 2 phases).

The Employee entity reads RTT_START_DATE from $_SERVER/$_ENV directly
since it has no DI. The resolver service is wired via services.yaml.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

config/services.yaml

@@ -39,6 +39,10 @@ services:
         arguments:
             $dataStartDate: '%env(RTT_START_DATE)%'
 
+    App\Service\Contracts\EmployeeContractPhaseResolver:
+        arguments:
+            $dataStartDate: '%env(RTT_START_DATE)%'
+
     App\Repository\Contract\AbsenceReadRepositoryInterface: '@App\Repository\AbsenceRepository'
     App\Repository\Contract\EmployeeContractPeriodReadRepositoryInterface: '@App\Repository\EmployeeContractPeriodRepository'
     App\Repository\Contract\EmployeeScopedRepositoryInterface: '@App\Repository\EmployeeRepository'