Add assembly and enclosure Circuit JSON elements

[seveibar]

Summary

• add source_assembly_device for product-level physical assembly identity
• add source_fdm_enclosure with direct assembly and selected-board relationships plus normalized enclosure dimensions
• add shape-discriminated source_cutout_aperture records owned by source components
• add cad_fdm_enclosure for positioned enclosure CAD/JSCAD output without synthetic PCB component ownership
• export all four schemas and include them in any_circuit_element
• add parsing, unit normalization, shape validation, and union coverage tests
• regenerate the Circuit JSON reference documentation

Why

The parametric enclosure flow needs first-class Circuit JSON records instead of retaining assembly/enclosure intent only in the live React tree and emitting enclosure CAD through synthetic source_component and pcb_component owners. These records make the product relationship and generated enclosure output explicit and serializable.

Initial relationships and scope

• source_fdm_enclosure.source_assembly_device_id identifies the physical product.
• source_fdm_enclosure.source_board_id stores the resolved board relationship rather than a TSX selector.
• source_cutout_aperture.source_component_id keeps aperture requirements part-owned.
• cad_fdm_enclosure.source_fdm_enclosure_id links generated CAD directly to its source enclosure.
• wall_thickness is required; optional dimensions and construction parameters preserve authoring flexibility.
• aperture geometry is limited to the currently released rect, pill, and circle contracts.
• mounting-stack/anchor and interaction-surface placement vocabularies are intentionally deferred until their public contracts stabilize.

Developer impact

Renderers can emit and consume enclosure source/CAD records directly through CircuitJson and any_circuit_element. CAD consumers can use JSCAD, standard model URLs, or model_asset without fabricating ECAD ownership records.

Validation

• bun test (264 passing)
• bunx tsc --noEmit
• bun run build
• bun run lint:zod
• bun run check-snake-case
• bunx biome format .
• bun run generate-docs