feat: support zeebe:formDefinition

[yT0n1]

Proposed Changes

Adds support for zeebe:formDefinition

related to camunda/camunda-modeler#5073

Checklist

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• Brief textual description of the changes present
• Visual demo attached
• Steps to try out present, i.e. using the @bpmn-io/sr tool
• Related issue linked via Closes {LINK_TO_ISSUE} or Related to {LINK_TO_ISSUE}

[Copilot]

Pull Request Overview

This PR adds support for zeebe:formDefinition by updating the validation error messages and introducing new test cases for both valid and broken form definition templates.

• Updated error message to include zeebe:formDefinition and zeebe:calledDecision as valid binding types.
• Added tests for valid form definition templates.
• Added tests for form definitions with binding errors.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
test/spec/validationSpec.js	Updated the valid binding types error message to support new options.
test/fixtures/form-definition.json	Added fixture for valid zeebe form definition templates.
test/fixtures/form-definition-broken.json	Added fixture testing error scenarios for zeebe form definition.

Comments suppressed due to low confidence (2)

test/spec/validationSpec.js:255

• Ensure that the updated error message is clearly documented and that related tests verify the presence of the new valid binding types.

          message: 'invalid property.binding type "zeebe:taskDefinition:foo"; must be any of { property, zeebe:taskDefinition:type, zeebe:input, zeebe:output, zeebe:property, zeebe:taskHeader, bpmn:Message#property, bpmn:Message#zeebe:subscription#property, zeebe:taskDefinition, zeebe:calledElement, zeebe:linkedResource, zeebe:userTask, zeebe:formDefinition, zeebe:calledDecision }'

test/fixtures/form-definition-broken.json:27

• [nitpick] Consider extending the test assertions to check for a specific error message or error detail for bindings with an invalid property value to further ensure validation robustness.

        }

[yT0n1]

merged with #56