Keep entries, notes and native progress

Number-grid progress is separate from clues

import {generateKazu,newKazuGame,toggleNote,encodeRun,encodeNotes,decodeRun,decodeNotes} from "@johnmorrisdotca/kazu";
const puzzle = generateKazu("number-place",4,"easy",42);
const game = newKazuGame(puzzle.kind,4,puzzle.givens)!;
const cell = game.printed.cells.findIndex(value=>value===0);
const noted = toggleNote(game,cell,1);
const restored = newKazuGame(puzzle.kind,4,puzzle.givens,{entries:decodeRun(encodeRun(noted.entries),4)!,notes:decodeNotes(encodeNotes(noted.notes),4)!});
console.log(restored?.notes[cell]);

2

Keep kind, size and the complete givens code with run/notes. Entries are zero on printed cells; notes use bit v for value v, not bit v-1. valuesOf combines clues with entries, and answerOf writes the current answer. Undo belongs to current game state; saved run text is not a promise to retain all undo history.

Dedicated families

Each family encodes its own board and marks using encodeShikaku, encodeHitori, encodeRegionsGame and corresponding decoders. Invalid encoded state returns null. Do not feed one family's progress into another just because their grids have the same dimensions.

The host decides whether to save/download text. Native frames read no storage, while the full demo retains its established local progress behavior. Keep assistance and elapsed time when your result policy uses them; a browser time is not a server proof. See encodings and embeds.