feat(repository): refactor query/mutation ports with capability-safe

interfaces

- refactor: split UserRepository into AuthUserRepository and
  AdminUserRepository capabilities
- refactor: split SessionRepository into AuthSessionRepository and
  repository-owned CLI/admin methods
- refactor: replace generic Repository Update/Delete with
  operation-specific params and ownership predicates
- refactor: replace CredentialRepository generic CRUD with
  passkey-specific methods
- refactor: replace FileRepository generic Create/Update/Delete with
  UploadedFileParams, DirectoryParams, and owned soft-delete
- refactor: remove repository fields from WebApp struct; repositories
  are now composition-time wiring only
- feat: add domain error kinds ErrParentNotFound, ErrParentNotDir,
  ErrDirectoryNotEmpty, ErrInvalidMove
- feat: add CredentialTypeAppPasskey constant
- feat: add testutil.SetUserAdmin for test fixture setup that bypasses
  production service ports
- test: add architecture test banning GORM Save in repository package
- test: add capability interface contract tests ensuring each service
  receives the minimal interface
- test: add blockingStorage helper for concurrent promotion tests
- test: add preserved DSN parameter test for sqliteImmediateDSN
- docs: update architecture decisions with repository write rules and
  capability separation
- docs: update roadmap to clarify atomic single-use refresh sessions
- docs: add -race test target to development docs

internal/service/admin.go

@@ -10,11 +10,11 @@ import (
 
 // AdminService handles administrator user-management operations.
 type AdminService struct {
-	userRepo repository.UserRepository
+	userRepo repository.AdminUserRepository
 }
 
 // NewAdminService creates an AdminService.
-func NewAdminService(userRepo repository.UserRepository) *AdminService {
+func NewAdminService(userRepo repository.AdminUserRepository) *AdminService {
 	return &AdminService{userRepo: userRepo}
 }
 
@@ -44,7 +44,7 @@ func (s *AdminService) DeleteUser(ctx context.Context, id string) error {
 	if _, err := s.GetUser(ctx, id); err != nil {
 		return err
 	}
-	if err := s.userRepo.Delete(ctx, id); err != nil {
+	if err := s.userRepo.MarkAdminDeleted(ctx, id); err != nil {
 		return model.NewInternalError("delete admin user", err)
 	}
 	return nil