feat(content): publish sealed Content snapshot APIs

[mysbryce]

Owners can create a Content API from a reviewed saved HTML preview, open its sealed draft in API Studio and explicitly publish a registered REST GET route. A current pinned runtime credential receives the literal document, escaped HTML and provenance. Later source edits or deletion do not change that snapshot.

Creation uses labelled forms and an exact six-key request. Other members cannot share or manage this owner-only API or its credentials/jobs. Stale reviews require explicit review; unconfirmed delivery blocks blind creation retry. This memory latch does not promise crash-safe idempotency. GraphQL Content APIs and live collection queries follow separately.

Validation:

• Full core: types, 411 backend cases/9,416 assertions, build and formatting. All 78 browser cases pass.
• The complete core/browser receipts precede one sharing-copy clarification. Six focused browser cases, final types/build/formatting and release policy pass after it.
• Final gallery: 1,336 PNGs/50 receipts, preserving 1,319 prior canonical metadata records. All 17 new and six affected legacy originals match promoted hashes; scoped review preserves scrolled-frame visibility limits.
• Fresh Windows portable: ten cases/1,202 assertions, including real Content creation/publication/caller behavior through the copied executable. All 13 portable originals reviewed.
• Exact executable and all 997 current source-input hashes verified. Original 713 notice files/276 components remain unchanged; zero new scopes.
• Clean committed source bundle: 1,052 files/24,409,522 bytes, exact source/payload hashes. Version 0.27.0-alpha.0, changelog and guides updated.

All three exact-head CI jobs pass for reviewed head 84c434a524a6f737e3a548f9638c068b33e8d7a8. No tag, new public executable or deployment is published. These checks do not certify production capacity or native-language accuracy.

Source delivery merged as 598cf847ff83454c0afe583e8d5b71e16846587d with the reviewed tree unchanged. All three main CI jobs passed before the remote and local delivery branches were deleted. Unrelated local main history was preserved.