Stage 1 of custom CMS pages. Adds type/published/meta/nav fields to
pages schema, splits changeset into system vs custom (with slug format
validation and reserved path exclusion), adds create/update/delete
functions with auto-redirect on slug change, and warms custom pages
in ETS cache. 62 pages tests, 1426 total.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
