Adds provider management control plane for Excititor: contracts, service,
endpoint group, focused tests. Matching plan shipped as
SPRINT_20260422_004_Concelier_full_connector_control_plane.md.
- VexProviderManagementContracts: request/response shapes
- ProviderManagementEndpoints: REST surface under the Excititor WebService
- VexProviderManagementService: business logic + persistence hooks
- ProviderManagementEndpointsTests: focused coverage
- TestAuthentication + csproj wiring updates for the new test surface
Work picked up mid-session; code was already on disk when this commit
series started. Bundling under the new sprint's plan here so the history
shows a coherent feature rather than a stray dirty diff.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
5c1b59580b