feat(workflows): support audio process outputs

[DrHepa]

Summary

• Allow process/model extension manifests to declare audio as an input/output type.
• Add audio badges/handle colors and preflight compatibility checks for audio workflow connections.
• Preserve audio process filePath results as outputPath without sending them to the 3D scene viewer.

Scope

This is intentionally minimal contract/routing support for audio artifacts. It does not add an audio player, asset library changes, or any Add-to-Scene behavior for audio.

Validation

• Ran git diff --check
• Reviewed the diff against upstream/dev
• TypeScript/tests not run in this clean worktree because dependencies are not installed

Notes

This enables extensions such as text-to-audio/SFX process nodes to return workspace audio files while keeping existing mesh/image/text behavior unchanged.