Provides formal validation and documentation for ComfyUI's /prompt API format.
Changes:
- schemas/prompt.json: Complete JSON Schema for prompt validation
- Validates node structure with class_type and inputs
- Supports direct values and node links [node_id, output_index]
- Includes examples for common workflows
- docs/api/prompt-schema.md: Comprehensive documentation
- Usage examples and validation guide
- Workflow vs Prompt format comparison
- Common node type reference
- Future enhancement roadmap
Benefits:
- Enables IDE autocomplete and validation
- Provides clear API specification
- Foundation for future dynamic schemas
- Resolves confusion about workflow vs prompt formats
Fixes#8899
[Bounty]
