feat: add schematic graphic props

[seveibar]

Summary

• add SchematicGraphicProps and schematicGraphicProps for <schematicgraphic />
• accept at least one graphic source: inline svgContent, an SVG imageUrl/static-file import, or both
• when both sources are supplied, treat imageUrl as the canonical asset source and svgContent as optional materialized fallback content
• expose optional width and height distance props, normalize unit strings to millimetres, and reject non-positive or non-finite dimensions
• report explicit validation errors for a missing source and empty source values
• allow name and displayName to be omitted from <schematicsheet> so a diagram-only page can use the concise nested form
• export the parser and type from the package entrypoint and regenerate the public props documentation

This is the props layer for embedding a system block diagram in a schematic sheet, including as the first page of a schematic PDF.

Related implementation chain:

• feat: add schematic graphic element circuit-json#730
• feat: render schematic graphic assets circuit-to-svg#695
• feat: support schematic sheet graphics core#3458

Preview package: https://pkg.pr.new/@tscircuit/props@b76321d

Testing

• bun test (461 passing)
• bun run typecheck
• bun run build
• bun run check-circular-deps
• bun run format:check
• git diff --check
• all required documentation generators