Add D3 grammar adapter and integration layer support

[YuktaSalvi2000]

Describe your changes

Describe your changes

This PR adds grammar-agnostic D3 visualization support through a shared adapter and integration-layer flow.

Main changes:

Added D3 grammar adapter support
Added visualization IR and integration-layer execution flow
Added grammar execution utilities
Updated registry/descriptors for grammar-based rendering
Added D3 example workflows and documentation
Added mock grammar adapter/testing utilities

Type of change (Check all that apply)

• New feature (non-breaking change which adds functionality)
• Documentation Update

Parts of Curio impacted by this PR:

• Frontend

Testing

• Executed npm run build in utk_curio/frontend/urban-workflows successfully.
• Manually loaded and verified D3 example workflows in Curio.

Screenshots (if relevant)

Checklist (Check all that apply)

• I have manually loaded each .json test from the tests/ folder into Curio, ran all the nodes one by one, and checked that they run without errors and give the expected results
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works