Add visual Workflow App authoring and first-use guidance

[temiroff]

What does this PR do?

Users can turn a workflow into an App through Create App: select parameters, results, and run buttons, then save and open the App. The first workspace now guides users to Text Pipeline and its visible Hello World result.

Changes

• Add a visual App designer using existing node schemas and operator-view contracts, with metadata-only updates that preserve workflow execution state.
• Support editing designer controls while retaining existing custom sections, settings, and safety controls; validate references before saving and deny authoring from packaged customer Apps.
• Keep App and node views connected through save/reload and the existing App packaging flow.
• Make starter templates easier to find and open with the keyboard, correct generic point-cloud labels, and document first use and App authoring.

Testing

• Full Python suite: 847 passed, 8 skipped.
• Editor unit tests: 17 passed; existing Playwright test passed; production build passed.
• Real browser/backend flow: create App, run Hello World, edit a parameter and see Acme World, switch views, save/reload, and reopen the designer with controls intact.
• Package creation from a clean source snapshot: ZIP includes the authored App, production UI, and Windows/Linux installers. Fresh-host installer execution was not tested.
• Staged diff whitespace check passed.

Managed-device delivery

• Runtime release not required. Changes are confined to editor UI, editor-server authoring metadata, tests, and documentation; delivery is through the core/editor release. The managed-device bundle and extension implementations are unchanged, so no Runtime bump or source-lock update is needed.
• Runtime release completed.

Related issues

No linked issue. This delivers visual App authoring; the complete dataset-to-trained-policy workflow remains a separate milestone.