feat(workflow-form): Form View page shell, load, and the shared spec harness #8018

Task Summary

The base of the Form View reader page: a new /user/workflow/:id/form page (WorkflowFormComponent), of which this task is the read-only shell.

• behind the formViewEnabled flag, load the workflow the URL names; redirect to the operator canvas when the workflow's default_view is not FORM or the flag is off
• show the workflow read-only, offer a switch back to the operator canvas
• release the shared singleton services on destroy
• add workflow-form.spec-harness.ts, the shared spec mock/factory the later page slices reuse

Independent of #8017 (the property-editor "choose exposed" task); this is the first slice of the reader-page track. The title bar/save, preview, inputs, running, results and authoring are separate follow-up tasks that build on this component.

Task Type

• Refactor / Cleanup
• DevOps / Deployment / CI
• Testing / QA
• Documentation
• Performance
• Other