theme.json v1 schema and validator

[tayebmokni]

Summary

Define the canonical theme.json v1 JSON Schema and ship a validator used at install time, in CI, and in the admin theme installer. The schema must cover settings (color, typography, spacing, layout, border, shadow, blocks), styles, supports, patterns, customTemplates, and templateParts. Output is published at https://gonext.dev/schemas/theme.json/v1.

Design reference

• docs/03-theme-system.md §3 (theme.json Specification)
• docs/03-theme-system.md §3.3 (Differences from WordPress's theme.json)

Acceptance criteria

• JSON Schema document published at the v1 URL, also vendored in-repo
• Covers every key in the §3.1 example
• Validator function exposed as a Go package and a TS module (shared fixtures)
• Rejects unknown top-level keys
• Validates spacing.spacingScale (operator, increment, steps, mediumStep, unit)
• Validates fluid font sizes (fontSizes[].fluid.min/max)
• Test suite of valid and invalid fixtures (≥20 cases)
• CLI: gonext theme validate ./my-theme/theme.json returns non-zero on failure with readable diagnostics

Dependencies

none

Complexity

M