Initial public release candidate of the LC-JSON (Learning Content JSON)
specification. Conforming documents carry "specVersion": "1.0" and
reference schemas at https://lc-json.org/1.0-rc.1/*.schema.json.

The /1.0-rc.1/ URL path is the rc.1 publication location per
NORMATIVE.md §8.3; /1.0/ is reserved for 1.0 final.

Conformance corpus: 36/36 fixtures pass under --strict
(12 valid + 24 invalid).

Spec covers:
- Two document types: course (hierarchical) and questionSet (flat)
- 12 question types
- 5 item types (content, exercise, quiz, contentsequence, signpost)
- HTML safety policy (HTML_SAFETY.md)
- Accessibility requirements (ACCESSIBILITY.md)
- Validation rules (VALIDATION.md)