Provisioning: Default to folder sync only and block new instance sync repositories (#115569)

* Default to folder sync only and block new instance sync repositories

- Change default allowed_targets to folder-only in backend configuration
- Modify validation to only enforce allowedTargets on CREATE operations
- Add deprecation warning for existing instance sync repositories
- Update frontend defaults and tests to reflect new behavior

Fixes #619

* Update warning message: change 'deprecated' to 'not fully supported'

* Fix health check: don't validate allowedTargets for existing repositories

Health checks for existing repositories should treat them as UPDATE operations,
not CREATE operations, so they don't fail validation for instance sync target.

* Fix tests and update i18n translations

- Update BootstrapStep tests to reflect folder-only default behavior
- Run i18n-extract to update translation file structure

* Fix integration tests

* Fix tests

* Fix provisioning test wizard

* Fix fronted test

apps/provisioning/pkg/repository/validator_test.go

@@ -303,7 +303,8 @@ func TestValidateRepository(t *testing.T) {
 	validator := NewValidator(10*time.Second, []provisioning.SyncTargetType{provisioning.SyncTargetTypeFolder}, false)
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			errors := validator.ValidateRepository(tt.repository)
+			// Tests validate new configurations, so always pass isCreate=true
+			errors := validator.ValidateRepository(tt.repository, true)
 			require.Len(t, errors, tt.expectedErrs)
 			if tt.validateError != nil {
 				tt.validateError(t, errors)