v0.88.0

• Breaking (bindings + Rust API): a single canonical Card wire shape now
  flows in both directions. Core owns it as quillmark_core::CardWire (with
  From<&Card> / TryFrom<CardWire>); the WASM/Python bindings serialize and
  deserialize it instead of hand-rolling their own per-card translation. The
  flat CardInput { kind, fields?, body? } input type is removed:
  Document.pushCard / insertCard (push_card / insert_card) now accept the
  same Card shape they return ({ kind, payloadItems, … }), so a card from
  cards / removeCard / quill.seedCard feeds straight back in. Build a fresh
  card from a flat field map with the new Document.makeCard /
  Document.make_card helper. A stale { kind, fields } object is now a loud
  error (deny_unknown_fields), not a silently-empty card. The seeded per-card
  getters quill.seedMain / quill.seedCard (seed_main / seed_card) are
  exposed on both bindings, mirroring the Rust Quill::seed_main / seed_card.
• Breaking (Rust API): Document::push_card now returns
  Result<(), EditError> and, with insert_card, validates that the card's
  $kind is a valid, non-reserved composable kind — the cards-list invariant is
  enforced at the edit op rather than incidentally at Card::new.
• Breaking (bindings + Rust API): the schema-aware form view is removed.
  Quill::form / Quill::blank_main / Quill::blank_card (and the
  quill.form / blankMain / blankCard bindings) are gone, along with the
  Form / FormCard / FormFieldValue / FormFieldSource types. Validation
  diagnostics now flow through Quill::validate(&Document) -> Vec<Diagnostic>
  (quill.validate(doc) in WASM/Python), which forwards the canonical
  validation::* diagnostics and keeps the non-fatal validation::field_absent
  completeness signal that render demotes. Field values/defaults/order are a
  Document × quill.schema join the consumer performs directly. See
  docs/migrations/0.87-to-0.88.md.
• Breaking (diagnostics): the validation code validation::must_fill_absent
  is renamed validation::field_absent. "Must-fill" is now scoped to the
  blueprint communication surface (the <must-fill> sentinel and the fatal
  validation::must_fill_sentinel); an absent field is a non-fatal
  completeness signal, not a fill requirement, since the render floor
  zero-fills it. The schema cell axis is renamed accordingly: the no-default:
  cell is Unendorsed (was "Must Fill"), the antonym of Endorsed —
  consumers routing on the old code or label must update. Internally
  ValidationError::MustFillUnset { source } splits into FieldAbsent and
  MustFillSentinel and the MustFillSource enum is removed.
• Breaking (bindings + Rust API): the example reference document is
  removed. QuillConfig::example() and the Quill.example (WASM) /
  Quill.example (Python) getters are gone. Its "show me a filled-out one"
  role is served by seeding — Quill::seed_document() / Quill.seedDocument()
  / Quill.seed_document() — which returns a committed Document rather than
  an annotated string. The CLI render with no input file now renders the
  seeded document. Nothing consumed the example document's annotations (the
  authoring surface is blueprint()), so the projection collapses into the
  seed: internally the FillSource fork in blueprint emission is gone and the
  blueprint always renders default: else the <must-fill> sentinel.
• wasm: lower the npm package engines.node floor from >=24 to >=22.
  The runtime never required 24 — --weak-refs needs only Node 14.6+, and the
  using sugar that motivated the 24 floor is optional (a try / finally
  fallback covers Node 22). The aggressive floor hard-blocked installs on Node
  22 CI/dev images under engine-strict.
• wasm: Document.makeCard(kind, fields?, body?) now types fields as
  optional in the generated .d.ts (was required, contradicting its docs);
  omitting it yields an empty field map, as before.
• docs: fix the Quill.schema getter doc — the returned schema includes
  ui hints (it never stripped them); the stale "ui hints stripped" wording is
  corrected. The 0.87→0.88 migration guide now documents the fill flag's
  !fill-placeholder semantics and clarifies that seeding is example-filled,
  not a blank-form replacement.
• blueprint: flatten group_fields and drop the unused group label (#697).
• docs: document seeding (example → absent), fix a block-scalar prescan
  bug, and add commitment-ladder docs (#691).
• docs(canon): dedup field-resolution semantics into SCHEMAS (#692); note
  that released migration guides are era-accurate and immutable (#695); prune
  evolutionary information from comments and canon docs (#700).