fix(workflow): warn when unsupported condition nodes are dropped on save (#2182)

[mrveiss]

Summary

• Adds validation in handleSaveWorkflow to detect condition/parallel nodes and warn users they will be excluded from the saved workflow
• Adds "beta" badge to the condition node button in WorkflowCanvas with tooltip referencing Enhancement: Backend DAG execution for conditional workflow branching #2140

Root cause: exportCanvasToSteps() filters to type === 'step' only, silently dropping condition/parallel nodes. Until #2140 (full DAG execution) is implemented, users are now explicitly warned.

Test plan

• Add a condition node + step nodes to canvas
• Click Save — verify warning toast appears about unsupported nodes
• Verify workflow still saves with only the step nodes
• Verify condition button shows "beta" badge

Closes #2182

[github-actions]

✅ SSOT Configuration Compliance: Passing

🎉 No hardcoded values detected that have SSOT config equivalents!