feat(collections): save reviewed HTML settings

[mysbryce]

Owners can save collection-wide HTML settings through labelled forms. Settings keep an independent revision: saving classes or literal attributes leaves the collection's frozen model and saved content unchanged. Concurrent edits require explicit Reload; an unconfirmed save keeps the local draft and blocks retries until reviewed recovery.

The owner-only HTTP boundary validates bounded wire settings and hashes, saves metadata audit events atomically, and includes renderer records in migration/backup recovery. Dashboard controls preserve untouched wire values, current authority and pending-operation guards across seven languages and light/dark phone layouts. Saved settings remain separate from temporary HTML preview; selecting them for preview and publishing generated CMS endpoints follow in later deliveries.

Validation:

• Types, 406 backend cases/8,886 assertions, production build and whole-project formatting pass.
• All 72 browser cases pass, including actual peer conflicts, lost response recovery, literal wire preservation and pending controls.
• Full gallery: 1,305 PNGs/48 receipts, preserving all 1,283 previous canonical metadata records. Scoped original review covers 22 new and six affected images.
• Fresh compiled portable: ten cases/1,118 assertions, including an actual collection-settings save through the copied executable. All nine portable originals reviewed.
• Actual portable input hashes and unchanged notice scopes verified. Clean committed source bundle: 1,043 indexed files/24,226,822 bytes with matching source/payload hashes.
• Version 0.25.0-alpha.0, changelog, owner-facing guide and roadmap updated. All three exact-head CI jobs pass at reviewed head 8ffc1b358bc495718951cb0dad33ecd2e46aa8dc.

No tag, new public executable or deployment is published. Screenshots demonstrate scoped visual review, not native-speaker certification or production capacity.