Upgrade InstantPageBlock.blockQuote from (text, caption) to
(blocks: [InstantPageBlock], caption). Legacy inbound shapes (API
pageBlockBlockquote, Postbox "t", FlatBuffers text) lift into
[.paragraph(text)]; outbound stays on the legacy wire constructor for
empty/single-paragraph quotes and uses pageBlockBlockquoteBlocks
otherwise. V1/V2 renderers recurse into child blocks with a fixed 10pt
inter-child gap; markdown forward/reverse, entity-expressibility, and
preview text updated. pullQuote is unchanged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add a first-class `checked: Bool?` to InstantPageListItem (orthogonal to the
ordered-list `num`), replacing the prior sentinel-string-in-num prototype.
- Data model: enum third associated value on .text/.blocks; Postbox + a new
FlatBuffers `checkState` tri-state field (0=nil,1=unchecked,2=checked,
backward-compatible); Equatable.
- Transmission: read/write the native API `checkbox`=flags.0 / `checked`=flags.1
bits on all four PageListItem / PageListOrderedItem constructors, so checkbox
state survives the server round-trip for sender and recipients.
- Markdown: forward parser routes detected `[ ]`/`[x]` into `checked` (keeping
the real number for ordered items); reverse converter emits `- [ ]`/`- [x]`
so editing a rich message round-trips.
- Display: V1 + V2 layout detect via `item.checked`; the V2 renderer draws real
CheckNode artwork (was a placeholder); preview text shows a checkbox glyph
instead of leaking the old sentinel.
Spec: docs/superpowers/specs/2026-05-27-instantpage-list-checkbox-design.md
Plan: docs/superpowers/plans/2026-05-27-instantpage-list-checkbox.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
